#include<iostream>
#include<vector>
#include<unordered_set>
using namespace std;
void print(vector<int> &A) {
for(int i=0; i<A.size(); i++) {
cout << A[i] << " ";
}
cout << endl;
}
string makeString(vector<int> &A) {
string temp = "";
for(int i=0; i<A.size(); i++) {
temp += to_string(A[i]); // check this syntax
}
return temp;
}
void generatePermutations(vector<int> &A) {
unordered_set <string> set;
int n = A.size();
for(int i=0; i<n; i++) {
for(int j=0; j<n; j++) {
// make a string and check if it is already in the set
if(i!=j) {
swap(A[i], A[j]);
string temp = makeString(A);
if(set.find(temp) != set.end()) {
swap(A[i], A[j]);
continue;
}
set.insert(temp);
print(A);
swap(A[i], A[j]);
} else {
string temp = makeString(A); // 123
if(set.find(temp) != set.end()) continue;
set.insert(temp);
print(A);
}
}
}
return;
}
void generatePermutations2(vector<int> &A, int idx, unordered_set<string> &set, string temp) {
if(idx == A.size()) {
print(A);
set.insert(temp);
return;
}
for(int i=0; i<A.size(); i++) {
swap(A[i], A[idx]);
string temp = makeString(A);
if(set.find(temp) == set.end()) {
generatePermutations2(A, idx+1, set, temp);
}
swap(A[i], A[idx]);
}
}
int main() {
vector<int> A = {1, 2, 3};
unordered_set <string> set;
generatePermutations2(A, 0, set, "");
return 0;
}
