Problem_#59_XOR_decryption.cpp

#include <cstdio>
#include <iostream>
#include <sstream>
#include <string>
#include <cmath>
#include <cassert>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <deque>
using namespace std;
typedef long long ll;
typedef pair<double, double> dd;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vii> vvii;

bool allowed(char x){
	if((x >= 'a' && x <= 'z') || (x >= 'A' && x <= 'Z') || (x >= '0' && x <='9')){
		return true;
	}
	char allowed[11] = {' ', ')','(', ';', ':', ',', '.', '\'', '?', '-', '!'};
	for(int i=0;i<11;i++){
		if(x == allowed[i]) return true;
	}
	return false;
}

int main(){
	int n; cin >> n;
	vi v(n);
	for(int i=0;i<n;i++){
		cin >> v[i];
	}
	for(int a ='a';a<='z';a++){
		for(int b='a';b<='z';b++){
			for(int c='a';c<='z';c++){
				string key = ""; key += a; key += b; key += c;
				bool sat = true;
				for(int i=0;i<n;i++){
					int x = v[i]^key[i%3];
					if(!allowed(x)){
						sat = false;
						break;
					}
				}
				if(sat){
					cout << key <<endl;
					/*for(int i=0;i<n;i++){
						cout << char(v[i]^key[i%3]) <<" ";
					}
					cout << endl;*/
				}
			}
		}
	}
}