LeetCode 62 Unique Paths (递推)

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?



Above is a 3 x 7 grid. How many possible unique paths are there?

题目链接：https://leetcode.com/problems/unique-paths/
题目分析：当前点可以从上边或者左边走来

public class Solution {
public int uniquePaths(int m, int n) {
int[][] dp = new int[m]
;
for (int i = 0; i < m; i ++) {
for (int j = 0; j < n; j ++) {
dp[i][j] = 0;
}
}
dp[0][0] = 1;
for (int i = 0; i < m; i ++) {
for (int j = 0; j < n; j ++) {
if (i - 1 >= 0) {
dp[i][j] += dp[i - 1][j];
}
if (j - 1 >= 0) {
dp[i][j] += dp[i][j - 1];
}
}
}
return dp[m - 1][n - 1];
}
}