Search a 2D Matrix

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:

 

• Integers in each row are sorted from left to right.
• The first integer of each row is greater than the last integer of the previous row.

 

For example,

Consider the following matrix:

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

Given target = 3, return true.

class Solution {
public:
    bool searchMatrix(vector<vector<int> > &matrix, int target) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int row = matrix.size() -1;
        int col = 0;
        while(row >= 0 && col < matrix[0].size()){
            if (matrix[row][col] > target){
                row--;
            }else if (matrix[row][col] < target){
                col++;
            }else{
                return true;
            }
        }
        return false;
    }
};