Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:
For example,
Consider the following matrix:
[ [1, 3, 5, 7], [10, 11, 16, 20], [23, 30, 34, 50] ]
Given target = 3, return true.
tag: 坐标转换 . 二分法 。binary search
public class Solution {
public boolean searchMatrix(int[][] matrix, int target) {
if(matrix == null || matrix.length == 0 || matrix[0] == null || matrix[0].length == 0){
return false;
}
int rows = matrix.length;
int cols = matrix[0].length;
int length = rows * cols;
int left = 0;
int right = length - 1;
while(left < right - 1){
int mid = left + (right - left) / 2;
int row = mid / cols;
int col = mid % cols;
if(matrix[row][col] == target){
return true;
}else if(matrix[row][col] < target){
left = mid;
}else{
right = mid;
}
}
if(matrix[left / cols][left % cols] == target){
return true;
}
if(matrix[right / cols][right % cols] == target){
return true;
}
return false;
}
}
原文：http://www.cnblogs.com/superzhaochao/p/6498094.html