标签：robot possible nbsp i++ ted ini col class turn
A robot is located at the top-left corner of a m x n grid (marked ‘Start‘ in the diagram below).
The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked ‘Finish‘ in the diagram below).
How many possible unique paths are there?
Solution:
Space: O(M * N)
class Solution { public int uniquePaths(int m, int n) { int [] paths = new int[m][n]; for (int i = 0; i < m; i++) { paths[i][0] = 1; } for (int i = 0; i < n; i++) { paths[0][i] = 1; } for (int i = 1; i < m; i++) { for (int j = 1; j < n; j++) { paths[i][j] = paths[i - 1][j] + paths[i][j - 1]; } } return paths[m - 1][n - 1]; } }
Optimized Space to O(N)
class Solution { public int uniquePaths(int m, int n) { if (m == 0 || n == 0) { return 0; } if (m == 1 ||n == 1) { return 1; } int [] paths = new int[n]; Arrays.fill(paths, 1); for (int i = 1; i < m; i++) { for (int j = 1; j < n; j++) { paths[j] += paths[j - 1]; } } return paths[n - 1]; } }
标签：robot possible nbsp i++ ted ini col class turn
原文地址：https://www.cnblogs.com/xuanlu/p/12047185.html
