题意
题解
方法一：两次次二分查找
class Solution {
public:
bool searchMatrix(vector<vector<int>> matrix, int target) {
auto row = upper_bound(matrix.begin(), matrix.end(), target, [](const int b, const vector<int> &a) {
return b < a[0];
});
if (row == matrix.begin()) {
return false;
}
--row;
return binary_search(row->begin(), row->end(), target);
}
};
方法二：一次二分查找
class Solution {
public:
bool searchMatrix(vector<vector<int>>& matrix, int target) {
int m = matrix.size();
int n = matrix[0].size();
int len = m * n;
int left = 0, right = len;
while(left < right) {
int mid = (left + right) / 2;
int i = mid / n, j = mid % n;
if(matrix[i][j] == target)
return true;
else if (matrix[i][j] < target) {
left = left + 1;
} else {
right = mid;
}
}
return false;
}
};