二分

C++ 代码

class Solution {
public:
    bool searchArray(vector<vector<int>> array, int target) {
        int n = array.size();
        if(n == 0)  return false;
        int m = array[0].size();

        int i = 0, j = m - 1;
        while(i < n && j >= 0){
            if(array[i][j] == target) return true;
            else if(array[i][j] > target) -- j;
            else ++ i;
        }
        return false;
    }
};