Search a 2D Matrix II

Write an efficient algorithm that searches for a value target in an m x n integer matrix 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.

 

Example 1:

Input: 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]], target = 5
Output: true

Example 2:

Input: 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]], target = 20 

Output: false 

Solution

class Solution {

public boolean searchMatrix(int[][] matrix, int target) {

int row=0;

int col=matrix[0].length-1;

if(target < matrix[0][0] || target > matrix[matrix.length-1][matrix[0].length-1]) {

return false;

}

while(row<matrix.length && col>=0){

if(target < matrix[row][col]) {

col--;

}

else if(target > matrix[row][col]) {

row++;

} else {

return true;

}

}

return false;

}

}