[leetcode] Minimum Path Sum

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Minimum Path Sum

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.

 思路：

只能向下和向右移動，那就很簡單了。動態規劃，當前最小和=當前值+當前點上方或者左方最小和，注意邊界情況。

題解：

class Solution {public:    int minPathSum(vector<vector<int> > &grid) {        int row = grid.size();        int col = grid[0].size();        if(row==0 || col==0)            return 0;        int **dp = new int*[row];        for(int i=0;i<row;i++)            dp[i] = new int[col];        for(int i=0;i<row;i++)            for(int j=0;j<col;j++) {                if(i==0 && j==0)                    dp[0][0] = grid[0][0];                else if(i==0)                    dp[0][j] = grid[0][j]+dp[0][j-1];                else if(j==0)                    dp[i][0] = grid[i][0]+dp[i-1][0];                else                    dp[i][j] = grid[i][j]+min(dp[i-1][j], dp[i][j-1]);            }        return dp[row-1][col-1];    }};

 

[leetcode] Minimum Path Sum