#include <bits/stdc++.h>
using namespace std;
void func(int idx, vector<int>&v, vector<vector<int>>&ans,vector<int>& temp){
	if(idx>= (int)v.size()){
		ans.push_back(temp);
		temp={};
		return;}
	temp.push_back(v[idx]);
	func(idx+1,v,ans,temp);
	temp.erase(temp.begin()+idx);
	func(idx+1,v,ans,temp);
}
 
int main() {
	vector<int>v = {3, 1 ,2};
	vector<int>temp;
	vector<vector<int>>ans;
	for(int i=0;i<ans.size();i++){
		for(int j=0;j<ans[i].size();j++)
		cout<<ans[i][j]<<" ";
		cout<<endl;
	}
}

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