leetcode 64 Minimum Path Sum ----- java

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.

还是之前题的延伸，求最小路径。还是可以在之前的版本上延伸。其实都是62题的变种，理解了dp，其实就都不难。

public class Solution {
    public int minPathSum(int[][] grid) {
        int m = grid.length;
        int n = grid[0].length;
        if( m == 0 || n == 0)
            return 0;
        int result = 0;
        if( m == 1){
            for( int i = 0;i<n;i++)
                result+=grid[0][i];
            return result;
        }
        if( n == 1){
            for( int i = 0;i<m;i++){
                result += grid[i][0];
            }
            return result;
        }
        int[] dp = new int[n];
        dp[0] = grid[0][0];
        for( int i = 1 ;i<n;i++){
            dp[i] = dp[i-1]+grid[0][i];
        }
        for( int i = 1;i<m;i++){
            dp[0] = dp[0]+grid[i][0];
            for( int j = 1;j<n;j++){
                dp[j] = dp[j]>dp[j-1]?dp[j-1]+grid[i][j]:dp[j]+grid[i][j];
            }
        }
        return dp[n-1];
        
        
        
        
    }
}