Leetcode Minimum Path Sum

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利用动态规划的思想求解

temp数组中存放从top left到第i 航，第j列的最短距离（i , j 从1开始算起）

temp[i][j] = min(grid[i-1][j-1]+temp[i-1][j],grid[i-1][j-1]+temp[i][j-1]); i>1&&j>1

temp[i][j] = grid[i-1][j-1]+temp[i-1][j]; i>1&&j==1

temp[i][j] = grid[i-1][j-1]+temp[i][j-1]; i==1&&j>1

temp[i][j] = grid[i-1][j-1]; i==1&&j==1

import java.util.Scanner;public class MinimumPathSum {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubScanner scan = new Scanner(System.in);int m = scan.nextInt();int n = scan.nextInt();int[][] grid = new int[m][n];for(int i = 0;i<m;i++){for(int j = 0;j<n;j++){grid[i][j] = scan.nextInt();}}MinimumPathSum mps = new MinimumPathSum();System.out.println(mps.minPathSum(grid));} public int minPathSum(int[][] grid) {     int m = grid.length;     int n = grid[0].length;     if(m==0||n==0)     return 0;     int temp[][] = new int[m+1][n+1];     for(int i = 1;i<m+1;i++){     for(int j =1;j<n+1;j++){     if(i!=1&&j!=1)     temp[i][j] = min(grid[i-1][j-1]+temp[i-1][j],grid[i-1][j-1]+temp[i][j-1]);     else if(i!=1){     temp[i][j] = grid[i-1][j-1]+temp[i-1][j];     }     else if(j!=1){     temp[i][j] = grid[i-1][j-1]+temp[i][j-1];     }     else      temp[i][j] = grid[i-1][j-1];     }     }     return temp[m][n]; }  public int min(int a, int b){ return (a<b)?a:b; }}

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