leetcode 64. 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.

Example 1:

[[1,3,1],
 [1,5,1],
 [4,2,1]]

Given the above grid map, return  7. Because the path 1→3→1→1→1 minimizes the sum.

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明显动态规划

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