[LeetCode]62. Unique Paths&&動態規劃
阿新 • • 發佈:2018-12-24
Unique Paths
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?
採用動態規劃對於格點(i,j)。由於只能從上格點(i-1,j)或左格點(i,j-1)到達,並且兩者路徑是不重複的
因此a[i][j] = ai-1][j]+a[i][j-1]
public int uniquePaths(int m, int n) { int a[][]=new int[m][n]; for(int i=0;i<n;i++) a[0][i]=1; for(int i=0;i<m;i++) a[i][0]=1; for(int i=1;i<m;i++) for(int j=1;j<n;j++) a[i][j]=a[i-1][j]+a[i][j-1]; return a[m-1][n-1]; }