240. Search a 2D Matrix II -- 【M】Amazon Google Apple / DC / Binary Search
https://leetcode.com/problems/search-a-2d-matrix-ii/
https://discuss.leetcode.com/topic/20064/my-concise-o-m-n-java-solution/2
时间：O(m + n)
public class Solution {
public boolean searchMatrix(int[][] matrix, int target) {
if (matrix == null || matrix.length == 0 || matrix[0].length == 0)
return false;
int row = 0;
int col = matrix[0].length - 1;
while (row < matrix.length && col >= 0) {
if (target == matrix[row][col])
return true;
else if (target > matrix[row][col])
row++;
else
col--;
}
return false;
}
}
*总结：
本质：一直部分有序2D array search target. 行递增列递增下一行头不一定比上一行尾大。所以不能用两次二分先找row的方法了。从右上角开始遍历，target大于它的row+1, target小于它的col-1