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feat: add solutions to lc problem: No.0157
No.0157.Read N Characters Given Read4
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‎solution/0100-0199/0157.Read N Characters Given Read4/README.md

Lines changed: 133 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -91,22 +91,154 @@ read4(buf4); // read4 返回 0。现在 buf = ""，fp 指向文件末
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<!-- 这里可写通用的实现逻辑 -->
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**方法一：模拟**
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直接模拟读取文件的过程，每次读取 4 个字符，然后将读取的字符存入缓存数组中，直到读取的字符数目达到 n 或者文件读取完毕。
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时间复杂度 $O(n)$。其中 $n$ 为要读取的字符数目。
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<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
101-
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"""
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The read4 API is already defined for you.
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@param buf4, a list of characters
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@return an integer
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def read4(buf4):
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# Below is an example of how the read4 API can be called.
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file = File("abcdefghijk") # File is "abcdefghijk", initially file pointer (fp) points to 'a'
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buf4 = [' '] * 4 # Create buffer with enough space to store characters
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read4(buf4) # read4 returns 4. Now buf = ['a','b','c','d'], fp points to 'e'
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read4(buf4) # read4 returns 4. Now buf = ['e','f','g','h'], fp points to 'i'
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read4(buf4) # read4 returns 3. Now buf = ['i','j','k',...], fp points to end of file
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"""
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class Solution:
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def read(self, buf, n):
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"""
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:type buf: Destination buffer (List[str])
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:type n: Number of characters to read (int)
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:rtype: The number of actual characters read (int)
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"""
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i = 0
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buf4 = [0] * 4
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v = 5
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while v >= 4:
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v = read4(buf4)
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for j in range(v):
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buf[i] = buf4[j]
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i += 1
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if i >= n:
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return n
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return i
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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/**
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* The read4 API is defined in the parent class Reader4.
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* int read4(char[] buf4);
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*/
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public class Solution extends Reader4 {
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/**
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* @param buf Destination buffer
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* @param n Number of characters to read
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* @return The number of actual characters read
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*/
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public int read(char[] buf, int n) {
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char[] buf4 = new char[4];
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int i = 0, v = 5;
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while (v >= 4) {
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v = read4(buf4);
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for (int j = 0; j < v; ++j) {
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buf[i++] = buf4[j];
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if (i >= n) {
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return n;
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}
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}
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}
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return i;
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}
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}
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```
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### **C++**
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```cpp
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/**
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* The read4 API is defined in the parent class Reader4.
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* int read4(char *buf4);
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*/
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class Solution {
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public:
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/**
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* @param buf Destination buffer
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* @param n Number of characters to read
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* @return The number of actual characters read
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*/
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int read(char *buf, int n) {
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char buf4[4];
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int i = 0, v = 5;
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while (v >= 4) {
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v = read4(buf4);
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for (int j = 0; j < v; ++j) {
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buf[i++] = buf4[j];
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if (i >= n) {
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return n;
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}
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}
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}
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return i;
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}
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};
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```
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### **Go**
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```go
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/**
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* The read4 API is already defined for you.
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*
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* read4 := func(buf4 []byte) int
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*
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* // Below is an example of how the read4 API can be called.
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* file := File("abcdefghijk") // File is "abcdefghijk", initially file pointer (fp) points to 'a'
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* buf4 := make([]byte, 4) // Create buffer with enough space to store characters
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* read4(buf4) // read4 returns 4. Now buf = ['a','b','c','d'], fp points to 'e'
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* read4(buf4) // read4 returns 4. Now buf = ['e','f','g','h'], fp points to 'i'
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* read4(buf4) // read4 returns 3. Now buf = ['i','j','k',...], fp points to end of file
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*/
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var solution = func(read4 func([]byte) int) func([]byte, int) int {
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// implement read below.
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return func(buf []byte, n int) int {
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buf4 := make([]byte, 4)
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i, v := 0, 5
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for v >= 4 {
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v = read4(buf4)
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for j := 0; j < v; j++ {
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buf[i] = buf4[j]
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i++
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if i >= n {
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return n
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}
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}
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}
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return i
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}
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}
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```
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### **...**

‎solution/0100-0199/0157.Read N Characters Given Read4/README_EN.md

Lines changed: 127 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -100,13 +100,139 @@ Note that &quot;abc&quot; is the file&#39;s content, not buf. buf is the destina
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### **Python3**
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```python
103-
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"""
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The read4 API is already defined for you.
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@param buf4, a list of characters
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@return an integer
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def read4(buf4):
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# Below is an example of how the read4 API can be called.
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file = File("abcdefghijk") # File is "abcdefghijk", initially file pointer (fp) points to 'a'
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buf4 = [' '] * 4 # Create buffer with enough space to store characters
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read4(buf4) # read4 returns 4. Now buf = ['a','b','c','d'], fp points to 'e'
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read4(buf4) # read4 returns 4. Now buf = ['e','f','g','h'], fp points to 'i'
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read4(buf4) # read4 returns 3. Now buf = ['i','j','k',...], fp points to end of file
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"""
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class Solution:
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def read(self, buf, n):
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"""
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:type buf: Destination buffer (List[str])
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:type n: Number of characters to read (int)
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:rtype: The number of actual characters read (int)
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"""
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i = 0
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buf4 = [0] * 4
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v = 5
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while v >= 4:
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v = read4(buf4)
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for j in range(v):
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buf[i] = buf4[j]
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i += 1
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if i >= n:
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return n
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return i
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```
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### **Java**
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108141
```java
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/**
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* The read4 API is defined in the parent class Reader4.
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* int read4(char[] buf4);
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*/
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public class Solution extends Reader4 {
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/**
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* @param buf Destination buffer
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* @param n Number of characters to read
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* @return The number of actual characters read
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*/
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public int read(char[] buf, int n) {
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char[] buf4 = new char[4];
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int i = 0, v = 5;
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while (v >= 4) {
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v = read4(buf4);
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for (int j = 0; j < v; ++j) {
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buf[i++] = buf4[j];
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if (i >= n) {
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return n;
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}
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}
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}
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return i;
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}
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}
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```
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### **C++**
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```cpp
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/**
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* The read4 API is defined in the parent class Reader4.
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* int read4(char *buf4);
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*/
177+
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class Solution {
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public:
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/**
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* @param buf Destination buffer
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* @param n Number of characters to read
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* @return The number of actual characters read
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*/
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int read(char *buf, int n) {
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char buf4[4];
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int i = 0, v = 5;
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while (v >= 4) {
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v = read4(buf4);
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for (int j = 0; j < v; ++j) {
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buf[i++] = buf4[j];
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if (i >= n) {
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return n;
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}
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}
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}
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return i;
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}
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};
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```
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### **Go**
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```go
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/**
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* The read4 API is already defined for you.
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*
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* read4 := func(buf4 []byte) int
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*
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* // Below is an example of how the read4 API can be called.
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* file := File("abcdefghijk") // File is "abcdefghijk", initially file pointer (fp) points to 'a'
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* buf4 := make([]byte, 4) // Create buffer with enough space to store characters
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* read4(buf4) // read4 returns 4. Now buf = ['a','b','c','d'], fp points to 'e'
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* read4(buf4) // read4 returns 4. Now buf = ['e','f','g','h'], fp points to 'i'
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* read4(buf4) // read4 returns 3. Now buf = ['i','j','k',...], fp points to end of file
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*/
217+
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var solution = func(read4 func([]byte) int) func([]byte, int) int {
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// implement read below.
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return func(buf []byte, n int) int {
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buf4 := make([]byte, 4)
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i, v := 0, 5
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for v >= 4 {
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v = read4(buf4)
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for j := 0; j < v; j++ {
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buf[i] = buf4[j]
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i++
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if i >= n {
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return n
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}
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}
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}
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return i
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}
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}
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```
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### **...**

‎solution/0100-0199/0157.Read N Characters Given Read4/Solution.cpp

Lines changed: 27 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,27 @@
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/**
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* The read4 API is defined in the parent class Reader4.
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* int read4(char *buf4);
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*/
5+
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class Solution {
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public:
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/**
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* @param buf Destination buffer
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* @param n Number of characters to read
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* @return The number of actual characters read
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*/
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int read(char *buf, int n) {
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char buf4[4];
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int i = 0, v = 5;
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while (v >= 4) {
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v = read4(buf4);
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for (int j = 0; j < v; ++j) {
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buf[i++] = buf4[j];
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if (i >= n) {
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return n;
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}
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}
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}
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return i;
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}
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};

‎solution/0100-0199/0157.Read N Characters Given Read4/Solution.go

Lines changed: 31 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,31 @@
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/**
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* The read4 API is already defined for you.
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*
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* read4 := func(buf4 []byte) int
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*
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* // Below is an example of how the read4 API can be called.
7+
* file := File("abcdefghijk") // File is "abcdefghijk", initially file pointer (fp) points to 'a'
8+
* buf4 := make([]byte, 4) // Create buffer with enough space to store characters
9+
* read4(buf4) // read4 returns 4. Now buf = ['a','b','c','d'], fp points to 'e'
10+
* read4(buf4) // read4 returns 4. Now buf = ['e','f','g','h'], fp points to 'i'
11+
* read4(buf4) // read4 returns 3. Now buf = ['i','j','k',...], fp points to end of file
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*/
13+
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var solution = func(read4 func([]byte) int) func([]byte, int) int {
15+
// implement read below.
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return func(buf []byte, n int) int {
17+
buf4 := make([]byte, 4)
18+
i, v := 0, 5
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for v >= 4 {
20+
v = read4(buf4)
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for j := 0; j < v; j++ {
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buf[i] = buf4[j]
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i++
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if i >= n {
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return n
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}
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}
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}
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return i
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}
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}

‎solution/0100-0199/0157.Read N Characters Given Read4/Solution.java

Lines changed: 26 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,26 @@
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/**
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* The read4 API is defined in the parent class Reader4.
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* int read4(char[] buf4);
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*/
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public class Solution extends Reader4 {
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/**
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* @param buf Destination buffer
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* @param n Number of characters to read
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* @return The number of actual characters read
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*/
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public int read(char[] buf, int n) {
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char[] buf4 = new char[4];
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int i = 0, v = 5;
15+
while (v >= 4) {
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v = read4(buf4);
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for (int j = 0; j < v; ++j) {
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buf[i++] = buf4[j];
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if (i >= n) {
20+
return n;
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}
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}
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}
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return i;
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}
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}

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