LeetCode: Minimum Path Sum

dp题，基本一次过

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

 C#

public class Solution {
    public int MinPathSum(int[,] grid) {
        int m = grid.GetLength(0);
        int n = grid.GetLength(1);
        if (m == 0 || n == 0) return 0;
        int[,] f = new int[m, n];
        f[0, 0] = grid[0, 0];
        for (int i = 1; i < m; i++) f[i, 0] = f[i-1, 0] + grid[i, 0];
        for (int i = 1; i < n; i++) f[0, i] = f[0, i-1] + grid[0, i];
        for (int i = 1; i < m; i++) {
            for (int j = 1; j < n; j++) {
                f[i, j] = Math.Min(f[i, j-1], f[i-1, j]) + grid[i, j];
            }
        }
        return f[m-1, n-1];
    }
}