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.

class Solution {

public:

int minPathSum(vector<vector<int> > &grid) 

{

    int m=grid.size();

    if(m==0)return 0;

    int n=grid[0].size();

    vector<int> ivec(n);

    vector<vector<int>> f(m, ivec);

    f[0][0]=grid[0][0];

    for (int ki=1;ki<m;ki++)

    {

        f[ki][0]=f[ki-1][0]+grid[ki][0];

    }

    for(int kj=1;kj<n;kj++)

    {

        f[0][kj]=f[0][kj-1]+grid[0][kj];

    }

    for (int i=1;i<m;i++)

    {

        for (int j=1;j<n;j++)

        {

            f[i][j]=min(f[i-1][j],f[i][j-1])+grid[i][j];

        }

    }

    return f[m-1][n-1];

}

};