62. Unique Paths && 63 Unique Paths II

https://leetcode.com/problems/unique-paths/

这道题，不利用动态规划基本上规模变大会运行超时，下面自己写得这段代码，直接暴力破解，只能应付小规模的情形，当23*12时就超时了：

class Solution {
public:
//    Solution():dp1(m,vector<int>(n,-1)),dp2(m,vector<int>(n,-1)){
        
//    }
    int uniquePaths(int m, int n) {
        helper(1,1,m,n,dp1,dp2);
        return res;
        
    }
    void helper(int row,int col,int m,int n,vector<vector<int>>& dp1,vector<vector<int>>& dp2){
        if(row==m && col==n){
            res++;
            return;
        }
        if(row<m&&col<n){
            helper(row+1,col,m,n,dp1,dp2);
            helper(row,col+1,m,n,dp1,dp2);
        }
        else if(row==m && col<n){
            helper(row,col+1,m,n,dp1,dp2);
        }
        else if(row<m && col==n){
            helper(row+1,col,m,n,dp1,dp2);
        }
    }
    
private:
    vector<vector<int>> dp1;
    vector<vector<int>> dp2;
    int res;
};

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