力扣 60

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每日打卡1

class Solution {
public:

    int jc(int x){
        int ans=1;
        for(int i=x;i>=1;i--) ans=ans*i;
        return ans;
    }

    string getPermutation(int n, int k) {
        if(n<=1) return "1";
       
        else{
            
           vector<string> num={"1","2","3","4","5","6","7","8","9"};
           string res;
           for(int i=1;i<=n;i++){

                int temp=jc(n-i);
                int l=ceil(double(k)/double(temp))-1;
                k=k-l*temp;
                res=res+num[l];
                num.erase (num.begin()+l);
           }
          return res;

        }
    }
};