之前写的题解

class Solution {
public:
    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        int n = matrix.size(), m = matrix[0].size();
        if (!n || !m) return false;
        int l = 0, r = n * m - 1;
        while (l < r) {
            int mid = l + r + 1 >> 1;
            if (matrix[mid / m][mid % m] <= target) l = mid;
            else r = mid - 1;
        }
        return matrix[l / m][l % m] == target;
        // if (matrix[l / m][l % m] == target) return true;
        // else return false;
    }
};