[LeetCode 240] Search a 2D matrix II

[LeetCode 240] Search a 2D matrix II

Write an efficient algorithm that searches for a value inMXNMatrix. 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]]

GivenTarget=5, Returntrue.

GivenTarget=20, Returnfalse.

Solution:

Search from matrix right top element, if smaller than target go left, if larger than target, go down.

Met this in Microsoft interview last year.

 

 

public boolean searchMatrix(int[][] matrix, int target) {        if(matrix.length <=0 || matrix[0].length <=0) return false;        int i = 0;        int j = matrix[0].length-1;        while(j>=0 && i