LeetCode 64

原题:

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.

题意：和前两题类似，选取路径最短的那一条

代码和思路：

class Solution {    public int minPathSum(int[][] grid) {        int m = grid.length;        int n = grid[0].length;                for(int i=0;i<m;i++){            for(int j=0;j<n;j++){                //处理第一行                if(i==0 && j !=0){                    grid[i][j] += grid[i][j-1];                }                //处理第一列                else if(j==0 && i!=0){                    grid[i][j] += grid[i-1][j];                }                //起始点                else if(i==0 && j==0){                    grid[i][j] = grid[i][j];                }                //因为路径可以从 左 和 上 过来。所以选取最小的那一条                else{                    grid[i][j] += Math.min(grid[i-1][j],grid[i][j-1]);                }            }        }        return grid[m-1][n-1];    }}