240 Search a 2D Matrix II.cpp

static int fastio=[](){
    std::ios::sync_with_stdio(false);
    cin.tie(NULL);
    return 0;
}();
class Solution {
    
public:
    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        if(matrix.size()==0)
            return false;
        if(matrix[0].size()==0)
            return false;
        
        int n=matrix.size();
        int m=matrix[0].size();
        
        int i=0;
        int j=m-1;
        while(i<n && j>=0){
            if(matrix[i][j]==target)
                return true;
            else if(matrix[i][j]>target)
                --j;
            else
                ++i;
        }
        return false;
    }
};