Java: Search a 2D Matrix

Difficulty Level: MEDIUM

Problem Statement:

You are given an m x n integer matrix matrix with the following two properties:

• Each row is sorted in non-decreasing order.
• The first integer of each row is greater than the last integer of the previous row.

Given an integer target, return true if the target is in the matrix or false otherwise.

Input:

matrix = [  
  [1,   3,  5,  7],  
  [10, 11, 16, 20],  
  [23, 30, 34, 50]  
]  

Output:

true
The sum of -1, -1 and 2 is 0. The Sum of -1, 0,  and 1 is also 0.