C++ | Leetcode C++题解之第393题UTF-8编码验证
题目：
题解：
class Solution {
public:
static const int MASK1 = 1 << 7;
static const int MASK2 = (1 << 7) + (1 << 6);
bool isValid(int num) {
return (num & MASK2) == MASK1;
}
int getBytes(int num) {
if ((num & MASK1) == 0) {
return 1;
}
int n = 0;
int mask = MASK1;
while ((num & mask) != 0) {
n++;
if (n > 4) {
return -1;
}
mask >>= 1;
}
return n >= 2 ? n : -1;
}
bool validUtf8(vector<int>& data) {
int m = data.size();
int index = 0;
while (index < m) {
int num = data[index];
int n = getBytes(num);
if (n < 0 || index + n > m) {
return false;
}
for (int i = 1; i < n; i++) {
if (!isValid(data[index + i])) {
return false;
}
}
index += n;
}
return true;
}
};