[Leetcode] Search a 2D Matrix

Title Description: (link)

Write an efficient algorithm, searches for a value in a m x n Matrix. 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 .

Problem Solving Ideas:

Two-point Search

1 classSolution {2  Public:3     BOOLSearchmatrix (vector<vector<int>>& Matrix,inttarget) {4         intFirst =0;5         intLast = Matrix.size ()-1;6         intLen = matrix[0].size ();7          while(First <=Last ) {8             intMID = first + (Last-first)/2;9             if(matrix[mid][0] <= target && target <= Matrix[mid][len-1] ) {Ten                 returnBinarySearch (Matrix[mid], target); One}Else if(matrix[mid][0] >target) { ALast = mid-1; -}Else if(Matrix[mid][len-1] <target) { -First = mid +1; the             } -         } -          -         return false; +     } -  + Private: A     BOOLBinarySearch (vector<int>& VEC,inttarget) { at         intFirst =0; -         intLast = Vec.size ()-1; -          while(First <=Last ) { -             intMid= first + (Last-first)/2; -             if(Vec[mid] = =target) { -                 return true; in}Else if(Vec[mid] <target) { -First = mid +1; to}Else { +Last = mid-1; -             } the         } *          $         return false;Panax Notoginseng     } -};

[Leetcode] Search a 2D Matrix