LeetCode 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?

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

Note: m and n will be at most 100.

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