Minimum Path Sum leetcode java

題目：

Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.

Note: You can only move either down or right at any point in time.

 

題解：

這道題跟Unique Path系列是思路一樣的。具體思路看程式碼就很清楚了

 

程式碼如下：

 

 1     public int minPathSum(int[][] grid) {
 2         int m = grid.length;
 3         int n = grid[0].length;
 4         
 5         if(m==0||n==0)
 6             return 0;
 7             
 8         int[][] dp = new int[m][n];
 9         
10         dp[0][0]=grid[0][0];
11         
12         //a row
13         for (int i = 1; i < n; i++) 
14             dp[0][i] = dp[0][i - 1] + grid[0][i];  
15 
16         //a column
17         for (int j = 1; j < m; j++)   
18             dp[j][0] = dp[j - 1][0] + grid[j][0];  
19         
20         for (int i=1; i<m; i++){  
21                 for (int j=1; j<n; j++){  
22                     if(dp[i-1][j]<dp[i][j-1])
23                         dp[i][j]=dp[i-1][j]+grid[i][j];
24                     else
25                         dp[i][j]=dp[i][j-1]+grid[i][j];
26                 }  
27             }  
28             return dp[m-1][n-1];  
29     }