LeetCode240——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.

实现：
class Solution {
public:
    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        int min = 0;
        while (min < matrix.size() && matrix[min][0] <= target) {
            if (searchMatrix(matrix[min], target)) {
                return true;
            }
            min++;
        }
        return false;
    }
    
    bool searchMatrix(vector<int>& matrix, int target) {
        int min = 0;
        int max = matrix.size()-1;
        int mid;
        while (min <= max) {
            mid = (min + max) / 2;
            if (matrix[mid] > target) {
                max = mid-1;
            } else if (matrix[mid] < target) {
                min = mid+1;
            } else {
                return true;
            }
        }
        return false;
    }
};

LeetCode240——Search a 2D Matrix II

原文：http://blog.csdn.net/booirror/article/details/47380941