LeetCode: Minimum Path Sum

dp题，基本一次过

 1 class Solution {

 2 public:

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

 4         // Start typing your C/C++ solution below

 5         // DO NOT write int main() function

 6         int m = grid.size();

 7         if (!m) return 0;

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

 9         if (!n) return 0;

10         vector<vector<int>> f(m, vector<int>(n));

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

12         for (int i = 1; i < m; i++) f[i][0] = f[i-1][0]+grid[i][0];

13         for (int i = 1; i < n; i++) f[0][i] = f[0][i-1]+grid[0][i];

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

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

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

17             }

18         }

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

20     }

21 };

 C#

 1 public class Solution {

 2     public int MinPathSum(int[,] grid) {

 3         int m = grid.GetLength(0);

 4         int n = grid.GetLength(1);

 5         if (m == 0 || n == 0) return 0;

 6         int[,] f = new int[m, n];

 7         f[0, 0] = grid[0, 0];

 8         for (int i = 1; i < m; i++) f[i, 0] = f[i-1, 0] + grid[i, 0];

 9         for (int i = 1; i < n; i++) f[0, i] = f[0, i-1] + grid[0, i];

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

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

12                 f[i, j] = Math.Min(f[i, j-1], f[i-1, j]) + grid[i, j];

13             }

14         }

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

16     }

17 }

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