Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:
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.
1、坐下角开始找。
2、也可以每行都用二分查找。
1 class Solution { 2 public: 3 bool searchMatrix(vector<vector<int>>& matrix, int target) { 4 int row = matrix.size() - 1; 5 if (row+1<=0) return false; 6 int col = 0; 7 while(col < int(matrix[0].size()) && row >= 0) { 8 if(matrix[row][col] > target) { 9 row--; 10 } else if (matrix[row][col] < target) { 11 col++; 12 } else { 13 return true; 14 } 15 } 16 return false; 17 } 18 };
240. Search a 2D Matrix II（二分查找）
原文：https://www.cnblogs.com/zle1992/p/12578089.html