Search a 2D Matrix系列

 

一、Search a 2D Matrix

 1 class Solution {
 2 public:
 3     bool searchMatrix(vector<vector<int>>& matrix, int target) {
 4          bool res = false;
 5          int row = -1;
 6          for(int i=1; i<matrix.size(); ++i)
 7          {
 8              if(target>=matrix[i-1][0] &&target<matrix[i][0])
 9              {
10                  row = i-1;
11                  break;
12              }
13          }
14          if(row == -1)
15               row = matrix.size()-1;
16         
17          for(int j=0; j<matrix[row].size(); ++j)
18                  if(target == matrix[row][j])
19                         return true;
20                  
21          return false;   
22     }
23 };

 

二、Search a 2D Matrix II

 1 class Solution {
 2 public:
 3     bool searchMatrix(vector<vector<int>>& matrix, int target) {
 4          if(matrix.empty() || target<matrix[0][0] )
 5                 return false;
 6          int row = matrix.size(), col = matrix[0].size();
 7          int i=row-1, j=0;
 8          while(i>=0 && j<col)
 9          {
10               if(matrix[i][j]==target)
11                     return true;
12               else if(matrix[i][j]<target)
13                         j++;
14               else if(matrix[i][j]>target) 
15                         i--;
16          } 
17          return false;  
18     }
19 };