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Jun 3, 2024
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feat: add solutions to lc problem: No.393 #3016

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ea88cb9
feat: add solutions to lc problem: No.393
yanglbme Jun 3, 2024
97b3adf
Update solution/0300-0399/0393.UTF-8 Validation/Solution.ts
thinkasany Jun 3, 2024
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123 changes: 84 additions & 39 deletions solution/0300-0399/0393.UTF-8 Validation/README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -79,7 +79,22 @@ tags:

<!-- solution:start -->

### 方法一
### 方法一：一次遍历

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 $cnt = 0$。

遍历数组中的每个整数，对于每个整数 $v$：

- 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。
- 如果 $v$ 的最高位为 $0$，则 $cnt = 0$。
- 如果 $v$ 的最高两位为 $110$，则 $cnt = 1$。
- 如果 $v$ 的最高三位为 $1110$，则 $cnt = 2$。
- 如果 $v$ 的最高四位为 $11110$，则 $cnt = 3$。
- 否则，返回 `false`。

最后，如果 $cnt = 0$，则返回 `true`，否则返回 `false`。

时间复杂度 $O(n)$，其中 $n$ 为数组 `data` 的长度。空间复杂度 $O(1)$。

<!-- tabs:start -->

Expand All @@ -88,50 +103,50 @@ tags:
```python
class Solution:
def validUtf8(self, data: List[int]) -> bool:
n = 0
cnt = 0
for v in data:
if n > 0:
if cnt > 0:
if v >> 6 != 0b10:
return False
n -= 1
cnt -= 1
elif v >> 7 == 0:
n = 0
cnt = 0
elif v >> 5 == 0b110:
n = 1
cnt = 1
elif v >> 4 == 0b1110:
n = 2
cnt = 2
elif v >> 3 == 0b11110:
n = 3
cnt = 3
else:
return False
return n == 0
return cnt == 0
```

#### Java

```java
class Solution {
public boolean validUtf8(int[] data) {
int n = 0;
int cnt = 0;
for (int v : data) {
if (n > 0) {
if (cnt > 0) {
if (v >> 6 != 0b10) {
return false;
}
--n;
--cnt;
} else if (v >> 7 == 0) {
n = 0;
cnt = 0;
} else if (v >> 5 == 0b110) {
n = 1;
cnt = 1;
} else if (v >> 4 == 0b1110) {
n = 2;
cnt = 2;
} else if (v >> 3 == 0b11110) {
n = 3;
cnt = 3;
} else {
return false;
}
}
return n == 0;
return cnt == 0;
}
}
```
Expand All @@ -142,23 +157,26 @@ class Solution {
class Solution {
public:
bool validUtf8(vector<int>& data) {
int n = 0;
int cnt = 0;
for (int& v : data) {
if (n > 0) {
if (v >> 6 != 0b10) return false;
--n;
} else if (v >> 7 == 0)
n = 0;
else if (v >> 5 == 0b110)
n = 1;
else if (v >> 4 == 0b1110)
n = 2;
else if (v >> 3 == 0b11110)
n = 3;
else
if (cnt > 0) {
if (v >> 6 != 0b10) {
return false;
}
--cnt;
} else if (v >> 7 == 0) {
cnt = 0;
} else if (v >> 5 == 0b110) {
cnt = 1;
} else if (v >> 4 == 0b1110) {
cnt = 2;
} else if (v >> 3 == 0b11110) {
cnt = 3;
} else {
return false;
}
}
return n == 0;
return cnt == 0;
}
};
```
Expand All @@ -167,26 +185,53 @@ public:

```go
func validUtf8(data []int) bool {
n := 0
cnt := 0
for _, v := range data {
if n > 0 {
if cnt > 0 {
if v>>6 != 0b10 {
return false
}
n--
cnt--
} else if v>>7 == 0 {
n = 0
cnt = 0
} else if v>>5 == 0b110 {
n = 1
cnt = 1
} else if v>>4 == 0b1110 {
n = 2
cnt = 2
} else if v>>3 == 0b11110 {
n = 3
cnt = 3
} else {
return false
}
}
return n == 0
return cnt == 0
}
```

#### TypeScript

```ts
function validUtf8(data: number[]): boolean {
let cnt = 0;
for (const v of data) {
if (cnt > 0) {
if (v >> 6 != 0b10) {
return false;
}
--cnt;
} else if (v >> 7 == 0) {
cnt = 0;
} else if (v >> 5 == 0b110) {
cnt = 1;
} else if (v >> 4 == 0b1110) {
cnt = 2;
} else if (v >> 3 == 0b11110) {
cnt = 3;
} else {
return false;
}
}
return cnt == 0;
}
```

Expand Down
123 changes: 84 additions & 39 deletions solution/0300-0399/0393.UTF-8 Validation/README_EN.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,22 @@ But the second continuation byte does not start with 10, so it is invalid.

<!-- solution:start -->

### Solution 1
### Solution 1: Single Pass

We use a variable $cnt$ to record the current number of bytes that need to be filled starting with $10$, initially $cnt = 0$.

For each integer $v$ in the array:

- If $cnt > 0$, then check if $v$ starts with $10$. If not, return `false`, otherwise decrement $cnt$.
- If the highest bit of $v$ is $0$, then $cnt = 0$.
- If the highest two bits of $v$ are $110$, then $cnt = 1$.
- If the highest three bits of $v$ are $1110$, then $cnt = 2$.
- If the highest four bits of $v$ are $11110$, then $cnt = 3$.
- Otherwise, return `false`.

Finally, if $cnt = 0$, return `true`, otherwise return `false`.

The time complexity is $O(n)$, where $n$ is the length of the array `data`. The space complexity is $O(1)$.

<!-- tabs:start -->

Expand All @@ -86,50 +101,50 @@ But the second continuation byte does not start with 10, so it is invalid.
```python
class Solution:
def validUtf8(self, data: List[int]) -> bool:
n = 0
cnt = 0
for v in data:
if n > 0:
if cnt > 0:
if v >> 6 != 0b10:
return False
n -= 1
cnt -= 1
elif v >> 7 == 0:
n = 0
cnt = 0
elif v >> 5 == 0b110:
n = 1
cnt = 1
elif v >> 4 == 0b1110:
n = 2
cnt = 2
elif v >> 3 == 0b11110:
n = 3
cnt = 3
else:
return False
return n == 0
return cnt == 0
```

#### Java

```java
class Solution {
public boolean validUtf8(int[] data) {
int n = 0;
int cnt = 0;
for (int v : data) {
if (n > 0) {
if (cnt > 0) {
if (v >> 6 != 0b10) {
return false;
}
--n;
--cnt;
} else if (v >> 7 == 0) {
n = 0;
cnt = 0;
} else if (v >> 5 == 0b110) {
n = 1;
cnt = 1;
} else if (v >> 4 == 0b1110) {
n = 2;
cnt = 2;
} else if (v >> 3 == 0b11110) {
n = 3;
cnt = 3;
} else {
return false;
}
}
return n == 0;
return cnt == 0;
}
}
```
Expand All @@ -140,23 +155,26 @@ class Solution {
class Solution {
public:
bool validUtf8(vector<int>& data) {
int n = 0;
int cnt = 0;
for (int& v : data) {
if (n > 0) {
if (v >> 6 != 0b10) return false;
--n;
} else if (v >> 7 == 0)
n = 0;
else if (v >> 5 == 0b110)
n = 1;
else if (v >> 4 == 0b1110)
n = 2;
else if (v >> 3 == 0b11110)
n = 3;
else
if (cnt > 0) {
if (v >> 6 != 0b10) {
return false;
}
--cnt;
} else if (v >> 7 == 0) {
cnt = 0;
} else if (v >> 5 == 0b110) {
cnt = 1;
} else if (v >> 4 == 0b1110) {
cnt = 2;
} else if (v >> 3 == 0b11110) {
cnt = 3;
} else {
return false;
}
}
return n == 0;
return cnt == 0;
}
};
```
Expand All @@ -165,26 +183,53 @@ public:

```go
func validUtf8(data []int) bool {
n := 0
cnt := 0
for _, v := range data {
if n > 0 {
if cnt > 0 {
if v>>6 != 0b10 {
return false
}
n--
cnt--
} else if v>>7 == 0 {
n = 0
cnt = 0
} else if v>>5 == 0b110 {
n = 1
cnt = 1
} else if v>>4 == 0b1110 {
n = 2
cnt = 2
} else if v>>3 == 0b11110 {
n = 3
cnt = 3
} else {
return false
}
}
return n == 0
return cnt == 0
}
```

#### TypeScript

```ts
function validUtf8(data: number[]): boolean {
let cnt = 0;
for (const v of data) {
if (cnt > 0) {
if (v >> 6 != 0b10) {
return false;
}
--cnt;
} else if (v >> 7 == 0) {
cnt = 0;
} else if (v >> 5 == 0b110) {
cnt = 1;
} else if (v >> 4 == 0b1110) {
cnt = 2;
} else if (v >> 3 == 0b11110) {
cnt = 3;
} else {
return false;
}
}
return cnt == 0;
}
```

Expand Down
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