64. 最小路径和

  1. class Solution {
  2.     public int minPathSum(int[][] grid) {
  3.         if (grid == null || grid.length == 0)
  4.             return 0;
  6.         int m = grid.length;
  7.         int n = grid[0].length;
  9.         int[][] dp = new int[m][n];
  10.         dp[0][0] = grid[0][0];
  12.         for (int j = 1; j < n; j++) 
  13.             dp[0][j] = dp[0][j - 1] + grid[0][j];
  15.         for (int i = 1; i < m; i++)
  16.             dp[i][0] = dp[i - 1][0] + grid[i][0];
  18.         for (int i = 1; i < m; i++) {
  19.             for (int j = 1; j < n; j++) {
  20.                 dp[i][j] = Math.min(dp[i - 1][j], dp[i][j - 1]) + grid[i][j];
  21.             }
  22.         }
  24.         return dp[m - 1][n - 1];
  25.     }
  26. }