[LeetCode]Search a 2D Matrix II

Search a 2D Matrix II

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:

• Integers in each row are sorted in ascending from left to right.
• Integers in each column are sorted in ascending from top to bottom.

For example,

Consider the following matrix:

[
  [1,   4,  7, 11, 15],
  [2,   5,  8, 12, 19],
  [3,   6,  9, 16, 22],
  [10, 13, 14, 17, 24],
  [18, 21, 23, 26, 30]
]

Given target = 5, return true.

Given target = 20, return false.

 

采用分治发，用上题的方法二代码即可，都不需要改的。

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