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feat: add solutions to lc problem: No.0065
No.0065.Valid Number
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‎solution/0000-0099/0065.Valid Number/README.md

+166-1
Original file line numberDiff line numberDiff line change
@@ -75,22 +75,187 @@
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<!-- 这里可写通用的实现逻辑 -->
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**方法一：分情况讨论**
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首先，我们判断字符串是否以正负号开头，如果是，将指针 $i$ 向后移动一位。如果此时指针 $i$ 已经到达字符串末尾，说明字符串只有一个正负号，返回 `false`。
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如果当前指针 $i$ 指向的字符是小数点，并且小数点后面没有数字，或者小数点后是一个 `e` 或 `E`，返回 `false`。
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接着，我们用两个变量 $dot$ 和 $e$ 分别记录小数点和 `e` 或 `E` 的个数。
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用指针 $j$ 指向当前字符：
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- 如果当前字符是小数点，并且此前出现过小数点或者 `e` 或 `E`，返回 `false`。否则，我们将 $dot$ 加一；
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- 如果当前字符是 `e` 或 `E`，并且此前出现过 `e` 或 `E`，或者当前字符是开头或结尾，返回 `false`。否则，我们将 $e$ 加一；然后判断下一个字符是否是正负号，如果是，将指针 $j$ 向后移动一位。如果此时指针 $j$ 已经到达字符串末尾，返回 `false`；
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- 如果当前字符不是数字，返回 `false`。
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遍历完字符串后，返回 `true`。
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时间复杂度 $O(n)$，空间复杂度 $O(1)$。其中 $n$ 为字符串长度。
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7896
<!-- 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
85-
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class Solution:
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def isNumber(self, s: str) -> bool:
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n = len(s)
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i = 0
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if s[i] in '+-':
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i += 1
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if i == n:
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return False
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if s[i] == '.' and (i + 1 == n or s[i + 1] in 'eE'):
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return False
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dot = e = 0
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j = i
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while j < n:
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if s[j] == '.':
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if e or dot:
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return False
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dot += 1
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elif s[j] in 'eE':
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if e or j == i or j == n - 1:
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return False
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e += 1
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if s[j + 1] in '+-':
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j += 1
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if j == n - 1:
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return False
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elif not s[j].isnumeric():
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return False
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j += 1
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return True
86132
```
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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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class Solution {
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public boolean isNumber(String s) {
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int n = s.length();
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int i = 0;
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if (s.charAt(i) == '+' || s.charAt(i) == '-') {
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++i;
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}
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if (i == n) {
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return false;
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}
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if (s.charAt(i) == '.' && (i + 1 == n || s.charAt(i + 1) == 'e' || s.charAt(i + 1) == 'E')) {
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return false;
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}
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int dot = 0, e = 0;
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for (int j = i; j < n; ++j) {
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if (s.charAt(j) == '.') {
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if (e > 0 || dot > 0) {
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return false;
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}
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++dot;
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} else if (s.charAt(j) == 'e' || s.charAt(j) == 'E') {
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if (e > 0 || j == i || j == n - 1) {
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return false;
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}
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++e;
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if (s.charAt(j + 1) == '+' || s.charAt(j + 1) == '-') {
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if (++j == n - 1) {
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return false;
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}
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}
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} else if (s.charAt(j) < '0' || s.charAt(j) > '9') {
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return false;
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}
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}
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return true;
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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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class Solution {
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public:
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bool isNumber(string s) {
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int n = s.size();
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int i = 0;
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if (s[i] == '+' || s[i] == '-') ++i;
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if (i == n) return false;
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if (s[i] == '.' && (i + 1 == n || s[i + 1] == 'e' || s[i + 1] == 'E')) return false;
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int dot = 0, e = 0;
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for (int j = i; j < n; ++j) {
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if (s[j] == '.') {
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if (e || dot) return false;
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++dot;
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} else if (s[j] == 'e' || s[j] == 'E') {
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if (e || j == i || j == n - 1) return false;
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++e;
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if (s[j + 1] == '+' || s[j + 1] == '-') {
198+
if (++j == n - 1) return false;
199+
}
200+
} else if (s[j] < '0' || s[j] > '9') return false;
201+
}
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return true;
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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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func isNumber(s string) bool {
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i, n := 0, len(s)
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if s[i] == '+' || s[i] == '-' {
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i++
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}
215+
if i == n {
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return false
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}
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if s[i] == '.' && (i+1 == n || s[i+1] == 'e' || s[i+1] == 'E') {
219+
return false
220+
}
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var dot, e int
222+
for j := i; j < n; j++ {
223+
if s[j] == '.' {
224+
if e > 0 || dot > 0 {
225+
return false
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}
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dot++
228+
} else if s[j] == 'e' || s[j] == 'E' {
229+
if e > 0 || j == i || j == n-1 {
230+
return false
231+
}
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e++
233+
if s[j+1] == '+' || s[j+1] == '-' {
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j++
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if j == n-1 {
236+
return false
237+
}
238+
}
239+
} else if s[j] < '0' || s[j] > '9' {
240+
return false
241+
}
242+
}
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return true
244+
}
245+
```
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### **C#**
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```cs
250+
using System.Text.RegularExpressions;
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public class Solution {
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private readonly Regex _isNumber_Regex = new Regex(@"^\s*[+-]?(\d+(\.\d*)?|\.\d+)([Ee][+-]?\d+)?\s*$");
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public bool IsNumber(string s) {
256+
return _isNumber_Regex.IsMatch(s);
257+
}
258+
}
94259
```
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96261
### **...**

‎solution/0000-0099/0065.Valid Number/README_EN.md

+148-1
Original file line numberDiff line numberDiff line change
@@ -72,13 +72,160 @@
7272
### **Python3**
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```python
75-
75+
class Solution:
76+
def isNumber(self, s: str) -> bool:
77+
n = len(s)
78+
i = 0
79+
if s[i] in '+-':
80+
i += 1
81+
if i == n:
82+
return False
83+
if s[i] == '.' and (i + 1 == n or s[i + 1] in 'eE'):
84+
return False
85+
dot = e = 0
86+
j = i
87+
while j < n:
88+
if s[j] == '.':
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if e or dot:
90+
return False
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dot += 1
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elif s[j] in 'eE':
93+
if e or j == i or j == n - 1:
94+
return False
95+
e += 1
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if s[j + 1] in '+-':
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j += 1
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if j == n - 1:
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return False
100+
elif not s[j].isnumeric():
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return False
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j += 1
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return True
76104
```
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### **Java**
79107

80108
```java
109+
class Solution {
110+
public boolean isNumber(String s) {
111+
int n = s.length();
112+
int i = 0;
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if (s.charAt(i) == '+' || s.charAt(i) == '-') {
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++i;
115+
}
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if (i == n) {
117+
return false;
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}
119+
if (s.charAt(i) == '.' && (i + 1 == n || s.charAt(i + 1) == 'e' || s.charAt(i + 1) == 'E')) {
120+
return false;
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}
122+
int dot = 0, e = 0;
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for (int j = i; j < n; ++j) {
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if (s.charAt(j) == '.') {
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if (e > 0 || dot > 0) {
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return false;
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}
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++dot;
129+
} else if (s.charAt(j) == 'e' || s.charAt(j) == 'E') {
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if (e > 0 || j == i || j == n - 1) {
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return false;
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}
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++e;
134+
if (s.charAt(j + 1) == '+' || s.charAt(j + 1) == '-') {
135+
if (++j == n - 1) {
136+
return false;
137+
}
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}
139+
} else if (s.charAt(j) < '0' || s.charAt(j) > '9') {
140+
return false;
141+
}
142+
}
143+
return true;
144+
}
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}
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```
147+
148+
### **C++**
149+
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```cpp
151+
class Solution {
152+
public:
153+
bool isNumber(string s) {
154+
int n = s.size();
155+
int i = 0;
156+
if (s[i] == '+' || s[i] == '-') ++i;
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if (i == n) return false;
158+
if (s[i] == '.' && (i + 1 == n || s[i + 1] == 'e' || s[i + 1] == 'E')) return false;
159+
int dot = 0, e = 0;
160+
for (int j = i; j < n; ++j) {
161+
if (s[j] == '.') {
162+
if (e || dot) return false;
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++dot;
164+
} else if (s[j] == 'e' || s[j] == 'E') {
165+
if (e || j == i || j == n - 1) return false;
166+
++e;
167+
if (s[j + 1] == '+' || s[j + 1] == '-') {
168+
if (++j == n - 1) return false;
169+
}
170+
} else if (s[j] < '0' || s[j] > '9') return false;
171+
}
172+
return true;
173+
}
174+
};
175+
```
176+
177+
### **Go**
178+
179+
```go
180+
func isNumber(s string) bool {
181+
i, n := 0, len(s)
182+
if s[i] == '+' || s[i] == '-' {
183+
i++
184+
}
185+
if i == n {
186+
return false
187+
}
188+
if s[i] == '.' && (i+1 == n || s[i+1] == 'e' || s[i+1] == 'E') {
189+
return false
190+
}
191+
var dot, e int
192+
for j := i; j < n; j++ {
193+
if s[j] == '.' {
194+
if e > 0 || dot > 0 {
195+
return false
196+
}
197+
dot++
198+
} else if s[j] == 'e' || s[j] == 'E' {
199+
if e > 0 || j == i || j == n-1 {
200+
return false
201+
}
202+
e++
203+
if s[j+1] == '+' || s[j+1] == '-' {
204+
j++
205+
if j == n-1 {
206+
return false
207+
}
208+
}
209+
} else if s[j] < '0' || s[j] > '9' {
210+
return false
211+
}
212+
}
213+
return true
214+
}
215+
```
216+
217+
### **C#**
218+
219+
```cs
220+
using System.Text.RegularExpressions;
221+
222+
public class Solution {
223+
private readonly Regex _isNumber_Regex = new Regex(@"^\s*[+-]?(\d+(\.\d*)?|\.\d+)([Ee][+-]?\d+)?\s*$");
81224

225+
public bool IsNumber(string s) {
226+
return _isNumber_Regex.IsMatch(s);
227+
}
228+
}
82229
```
83230

84231
### **...**

‎solution/0000-0099/0065.Valid Number/Solution.cpp

+24
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,24 @@
1+
class Solution {
2+
public:
3+
bool isNumber(string s) {
4+
int n = s.size();
5+
int i = 0;
6+
if (s[i] == '+' || s[i] == '-') ++i;
7+
if (i == n) return false;
8+
if (s[i] == '.' && (i + 1 == n || s[i + 1] == 'e' || s[i + 1] == 'E')) return false;
9+
int dot = 0, e = 0;
10+
for (int j = i; j < n; ++j) {
11+
if (s[j] == '.') {
12+
if (e || dot) return false;
13+
++dot;
14+
} else if (s[j] == 'e' || s[j] == 'E') {
15+
if (e || j == i || j == n - 1) return false;
16+
++e;
17+
if (s[j + 1] == '+' || s[j + 1] == '-') {
18+
if (++j == n - 1) return false;
19+
}
20+
} else if (s[j] < '0' || s[j] > '9') return false;
21+
}
22+
return true;
23+
}
24+
};

‎solution/0000-0099/0065.Valid Number/Solution.cs

+4-7
Original file line numberDiff line numberDiff line change
@@ -1,12 +1,9 @@
1-
// https://leetcode.com/problems/valid-number/
1+
using System.Text.RegularExpressions;
22

3-
using System.Text.RegularExpressions;
4-
5-
public partial class Solution
6-
{
3+
public class Solution {
74
private readonly Regex _isNumber_Regex = new Regex(@"^\s*[+-]?(\d+(\.\d*)?|\.\d+)([Ee][+-]?\d+)?\s*$");
8-
public bool IsNumber(string s)
9-
{
5+
6+
public bool IsNumber(string s) {
107
return _isNumber_Regex.IsMatch(s);
118
}
129
}

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