Search a 2D Matrix

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

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

For example,

Consider the following matrix:

[  [1,   3,  5,  7],  [Ten, One,],  [23, 30, 34, 50]]

given   target   =   3 , return   true .

#include <iostream> #include <vector>using namespace Std;bool Searchmatrix (vector<vector<int> > &matrix, int target) {if (Matrix.empty ()) return false;int length = Matrix[0].size (); int first = 0;int last = Matr Ix.size () *length-1;while (first<=last) {int mid = (first + last)/2;if (matrix[mid/length][mid%length] = = target) retu RN True;else if (Matrix[mid/length][mid%length] < target) First = mid + 1;elselast = mid-1;} return false;}

Search a 2D Matrix