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) {        vector<vector<int>> paths(m,vector<int>(n,0));        for(int i=0;i<m;++i){            for(int j=0;j<n;++j){                if(i==0 && j==0) {                    paths[i][j]=1;                    continue;                }                if(i>0 && j>0) paths[i][j] = paths[i-1][j]+paths[i][j-1];                else if(i>0) paths[i][j] = paths[i-1][j];                else paths[i][j] = paths[i][j-1];            }        }        return m ? paths[m-1][n-1]:0;    }};