Minimum Path Sum.cpp

class Solution {
public:
    int minPathSum(vector<vector<int> > &grid) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int len1 = grid.size(), len2 = grid[0].size();
        vector<vector<int> > sum(len1);
        for (int i = 0; i != len1; i++)
            sum[i].resize(len2);
        
        sum[0][0] = grid[0][0];
        for (int i = 1; i != len1; i++)
            sum[i][0] = sum[i-1][0] + grid[i][0];
        for (int i = 1; i != len2; i++)
            sum[0][i] = sum[0][i-1] + grid[0][i];
            
        for (int i = 1; i != len1; i++){
            for (int j = 1; j != len2; j++){
                sum[i][j] = grid[i][j] + min(sum[i-1][j], sum[i][j-1]);
            }
        }
        
        return sum[len1-1][len2-1];
    }
};