240. Search a 2D Matrix II.cpp

class Solution {
public:
    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        if(matrix.empty()) return false;
        const int m = matrix.size(), n = matrix[0].size();
        int i = 0, j = n - 1;
        while(i < m && j >= 0){
            if(matrix[i][j] == target)
                return true;
            else if(matrix[i][j] < target)
                i++;
            else
                j--;
        }
        return false;
    }
};