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yanglbmethinkasany
yanglbme
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thinkasany
authored
feat: add solutions to lc problem: No.393 (doocs#3016)
* feat: add solutions to lc problem: No.393 No.0393.UTF-8 Validation * Update solution/0300-0399/0393.UTF-8 Validation/Solution.ts --------- Co-authored-by: thinkasany <480968828@qq.com>
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‎solution/0300-0399/0393.UTF-8 Validation/README.md

+84-39
Original file line numberDiff line numberDiff line change
@@ -79,7 +79,22 @@ tags:
7979

8080
<!-- solution:start -->
8181

82-
### 方法一
82+
### 方法一：一次遍历
83+
84+
我们用一个变量 $cnt$ 记录当前需要填充的以 $10$ 开头的字节的个数，初始时 $cnt = 0$。
85+
86+
遍历数组中的每个整数，对于每个整数 $v$：
87+
88+
- 如果 $cnt > 0$，则判断 $v$ 是否以 $10$ 开头，如果不是，则返回 `false`，否则 $cnt$ 减一。
89+
- 如果 $v$ 的最高位为 $0$，则 $cnt = 0$。
90+
- 如果 $v$ 的最高两位为 $110$，则 $cnt = 1$。
91+
- 如果 $v$ 的最高三位为 $1110$，则 $cnt = 2$。
92+
- 如果 $v$ 的最高四位为 $11110$，则 $cnt = 3$。
93+
- 否则，返回 `false`。
94+
95+
最后，如果 $cnt = 0$，则返回 `true`，否则返回 `false`。
96+
97+
时间复杂度 $O(n)$，其中 $n$ 为数组 `data` 的长度。空间复杂度 $O(1)$。
8398

8499
<!-- tabs:start -->
85100

@@ -88,50 +103,50 @@ tags:
88103
```python
89104
class Solution:
90105
def validUtf8(self, data: List[int]) -> bool:
91-
n = 0
106+
cnt = 0
92107
for v in data:
93-
if n > 0:
108+
if cnt > 0:
94109
if v >> 6 != 0b10:
95110
return False
96-
n -= 1
111+
cnt -= 1
97112
elif v >> 7 == 0:
98-
n = 0
113+
cnt = 0
99114
elif v >> 5 == 0b110:
100-
n = 1
115+
cnt = 1
101116
elif v >> 4 == 0b1110:
102-
n = 2
117+
cnt = 2
103118
elif v >> 3 == 0b11110:
104-
n = 3
119+
cnt = 3
105120
else:
106121
return False
107-
return n == 0
122+
return cnt == 0
108123
```
109124

110125
#### Java
111126

112127
```java
113128
class Solution {
114129
public boolean validUtf8(int[] data) {
115-
int n = 0;
130+
int cnt = 0;
116131
for (int v : data) {
117-
if (n > 0) {
132+
if (cnt > 0) {
118133
if (v >> 6 != 0b10) {
119134
return false;
120135
}
121-
--n;
136+
--cnt;
122137
} else if (v >> 7 == 0) {
123-
n = 0;
138+
cnt = 0;
124139
} else if (v >> 5 == 0b110) {
125-
n = 1;
140+
cnt = 1;
126141
} else if (v >> 4 == 0b1110) {
127-
n = 2;
142+
cnt = 2;
128143
} else if (v >> 3 == 0b11110) {
129-
n = 3;
144+
cnt = 3;
130145
} else {
131146
return false;
132147
}
133148
}
134-
return n == 0;
149+
return cnt == 0;
135150
}
136151
}
137152
```
@@ -142,23 +157,26 @@ class Solution {
142157
class Solution {
143158
public:
144159
bool validUtf8(vector<int>& data) {
145-
int n = 0;
160+
int cnt = 0;
146161
for (int& v : data) {
147-
if (n > 0) {
148-
if (v >> 6 != 0b10) return false;
149-
--n;
150-
} else if (v >> 7 == 0)
151-
n = 0;
152-
else if (v >> 5 == 0b110)
153-
n = 1;
154-
else if (v >> 4 == 0b1110)
155-
n = 2;
156-
else if (v >> 3 == 0b11110)
157-
n = 3;
158-
else
162+
if (cnt > 0) {
163+
if (v >> 6 != 0b10) {
164+
return false;
165+
}
166+
--cnt;
167+
} else if (v >> 7 == 0) {
168+
cnt = 0;
169+
} else if (v >> 5 == 0b110) {
170+
cnt = 1;
171+
} else if (v >> 4 == 0b1110) {
172+
cnt = 2;
173+
} else if (v >> 3 == 0b11110) {
174+
cnt = 3;
175+
} else {
159176
return false;
177+
}
160178
}
161-
return n == 0;
179+
return cnt == 0;
162180
}
163181
};
164182
```
@@ -167,26 +185,53 @@ public:
167185
168186
```go
169187
func validUtf8(data []int) bool {
170-
n := 0
188+
cnt := 0
171189
for _, v := range data {
172-
if n > 0 {
190+
if cnt > 0 {
173191
if v>>6 != 0b10 {
174192
return false
175193
}
176-
n--
194+
cnt--
177195
} else if v>>7 == 0 {
178-
n = 0
196+
cnt = 0
179197
} else if v>>5 == 0b110 {
180-
n = 1
198+
cnt = 1
181199
} else if v>>4 == 0b1110 {
182-
n = 2
200+
cnt = 2
183201
} else if v>>3 == 0b11110 {
184-
n = 3
202+
cnt = 3
185203
} else {
186204
return false
187205
}
188206
}
189-
return n == 0
207+
return cnt == 0
208+
}
209+
```
210+
211+
#### TypeScript
212+
213+
```ts
214+
function validUtf8(data: number[]): boolean {
215+
let cnt = 0;
216+
for (const v of data) {
217+
if (cnt > 0) {
218+
if (v >> 6 != 0b10) {
219+
return false;
220+
}
221+
--cnt;
222+
} else if (v >> 7 == 0) {
223+
cnt = 0;
224+
} else if (v >> 5 == 0b110) {
225+
cnt = 1;
226+
} else if (v >> 4 == 0b1110) {
227+
cnt = 2;
228+
} else if (v >> 3 == 0b11110) {
229+
cnt = 3;
230+
} else {
231+
return false;
232+
}
233+
}
234+
return cnt == 0;
190235
}
191236
```
192237

‎solution/0300-0399/0393.UTF-8 Validation/README_EN.md

+84-39
Original file line numberDiff line numberDiff line change
@@ -77,7 +77,22 @@ But the second continuation byte does not start with 10, so it is invalid.
7777

7878
<!-- solution:start -->
7979

80-
### Solution 1
80+
### Solution 1: Single Pass
81+
82+
We use a variable $cnt$ to record the current number of bytes that need to be filled starting with $10$, initially $cnt = 0$.
83+
84+
For each integer $v$ in the array:
85+
86+
- If $cnt > 0$, then check if $v$ starts with $10$. If not, return `false`, otherwise decrement $cnt$.
87+
- If the highest bit of $v$ is $0$, then $cnt = 0$.
88+
- If the highest two bits of $v$ are $110$, then $cnt = 1$.
89+
- If the highest three bits of $v$ are $1110$, then $cnt = 2$.
90+
- If the highest four bits of $v$ are $11110$, then $cnt = 3$.
91+
- Otherwise, return `false`.
92+
93+
Finally, if $cnt = 0$, return `true`, otherwise return `false`.
94+
95+
The time complexity is $O(n)$, where $n$ is the length of the array `data`. The space complexity is $O(1)$.
8196

8297
<!-- tabs:start -->
8398

@@ -86,50 +101,50 @@ But the second continuation byte does not start with 10, so it is invalid.
86101
```python
87102
class Solution:
88103
def validUtf8(self, data: List[int]) -> bool:
89-
n = 0
104+
cnt = 0
90105
for v in data:
91-
if n > 0:
106+
if cnt > 0:
92107
if v >> 6 != 0b10:
93108
return False
94-
n -= 1
109+
cnt -= 1
95110
elif v >> 7 == 0:
96-
n = 0
111+
cnt = 0
97112
elif v >> 5 == 0b110:
98-
n = 1
113+
cnt = 1
99114
elif v >> 4 == 0b1110:
100-
n = 2
115+
cnt = 2
101116
elif v >> 3 == 0b11110:
102-
n = 3
117+
cnt = 3
103118
else:
104119
return False
105-
return n == 0
120+
return cnt == 0
106121
```
107122

108123
#### Java
109124

110125
```java
111126
class Solution {
112127
public boolean validUtf8(int[] data) {
113-
int n = 0;
128+
int cnt = 0;
114129
for (int v : data) {
115-
if (n > 0) {
130+
if (cnt > 0) {
116131
if (v >> 6 != 0b10) {
117132
return false;
118133
}
119-
--n;
134+
--cnt;
120135
} else if (v >> 7 == 0) {
121-
n = 0;
136+
cnt = 0;
122137
} else if (v >> 5 == 0b110) {
123-
n = 1;
138+
cnt = 1;
124139
} else if (v >> 4 == 0b1110) {
125-
n = 2;
140+
cnt = 2;
126141
} else if (v >> 3 == 0b11110) {
127-
n = 3;
142+
cnt = 3;
128143
} else {
129144
return false;
130145
}
131146
}
132-
return n == 0;
147+
return cnt == 0;
133148
}
134149
}
135150
```
@@ -140,23 +155,26 @@ class Solution {
140155
class Solution {
141156
public:
142157
bool validUtf8(vector<int>& data) {
143-
int n = 0;
158+
int cnt = 0;
144159
for (int& v : data) {
145-
if (n > 0) {
146-
if (v >> 6 != 0b10) return false;
147-
--n;
148-
} else if (v >> 7 == 0)
149-
n = 0;
150-
else if (v >> 5 == 0b110)
151-
n = 1;
152-
else if (v >> 4 == 0b1110)
153-
n = 2;
154-
else if (v >> 3 == 0b11110)
155-
n = 3;
156-
else
160+
if (cnt > 0) {
161+
if (v >> 6 != 0b10) {
162+
return false;
163+
}
164+
--cnt;
165+
} else if (v >> 7 == 0) {
166+
cnt = 0;
167+
} else if (v >> 5 == 0b110) {
168+
cnt = 1;
169+
} else if (v >> 4 == 0b1110) {
170+
cnt = 2;
171+
} else if (v >> 3 == 0b11110) {
172+
cnt = 3;
173+
} else {
157174
return false;
175+
}
158176
}
159-
return n == 0;
177+
return cnt == 0;
160178
}
161179
};
162180
```
@@ -165,26 +183,53 @@ public:
165183
166184
```go
167185
func validUtf8(data []int) bool {
168-
n := 0
186+
cnt := 0
169187
for _, v := range data {
170-
if n > 0 {
188+
if cnt > 0 {
171189
if v>>6 != 0b10 {
172190
return false
173191
}
174-
n--
192+
cnt--
175193
} else if v>>7 == 0 {
176-
n = 0
194+
cnt = 0
177195
} else if v>>5 == 0b110 {
178-
n = 1
196+
cnt = 1
179197
} else if v>>4 == 0b1110 {
180-
n = 2
198+
cnt = 2
181199
} else if v>>3 == 0b11110 {
182-
n = 3
200+
cnt = 3
183201
} else {
184202
return false
185203
}
186204
}
187-
return n == 0
205+
return cnt == 0
206+
}
207+
```
208+
209+
#### TypeScript
210+
211+
```ts
212+
function validUtf8(data: number[]): boolean {
213+
let cnt = 0;
214+
for (const v of data) {
215+
if (cnt > 0) {
216+
if (v >> 6 != 0b10) {
217+
return false;
218+
}
219+
--cnt;
220+
} else if (v >> 7 == 0) {
221+
cnt = 0;
222+
} else if (v >> 5 == 0b110) {
223+
cnt = 1;
224+
} else if (v >> 4 == 0b1110) {
225+
cnt = 2;
226+
} else if (v >> 3 == 0b11110) {
227+
cnt = 3;
228+
} else {
229+
return false;
230+
}
231+
}
232+
return cnt == 0;
188233
}
189234
```
190235

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