蒟蒻的代码，只有 $20pts$，求大佬帮助。

#include <bits/stdc++.h>
using namespace std;
string s;
int a[220];
int main() {
	cin>>s;
    int len=s.size ();
	for (int i=1;i<=len;i++)
		a[i]=int (s[i-1]-'a'+1);
	do {
		for (int i=1;i<=len;i++)
			cout<<char ('a'+a[i]-1);
		cout<<"\n";
	} while (next_permutation (a+1,a+1+len));
	return 0;
}