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;

}

};

版权声明：本文为博主原创文章，未经博主允许不得转载。