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.
最经典的动态规划题之一,就不用多说了
public class Solution {
public int minPathSum(int[][] grid) {
if(grid==null) return 0;
int h = grid.length;
int w = grid[0].length;
if(h==0||w==0) return 0;
int[][] dp = new int[h][w];
dp[0][0] = grid[0][0];
for(int j=1; j < w; j++){
dp[0][j] = dp[0][j-1] + grid[0][j];
}
for(int i=1; i< h; i++){
dp[i][0] = dp[i-1][0] + grid[i][0];
}
for(int i=1; i<h;i++){
for(int j=1; j<w; j++){
dp[i][j] = Math.min(dp[i-1][j], dp[i][j-1]) + grid[i][j];
}
}
return dp[h-1][w-1];
}
}