[백준/백트래킹/C++] 6603번 로또

https://www.acmicpc.net/problem/6603

6603번: 로또

#include <bits/stdc++.h>

using namespace std;

int k;
int num[50], arr[50];
bool isused[50];

void backtrack(int k, int n){
    if(k==6){
        bool flag = true;
        int tmp = -1;
        for(int i=0; i<6; i++){ // 오름차순 체크
            if(tmp > arr[i]) flag = false;
            tmp = arr[i];
        }

        if(flag){
            for(int i=0; i<6; i++)
                cout << arr[i] << ' ';
            cout << '\n';
        }
        return;
    }
    int st = 0;
    if(k!=0) st = k-1;
    for(int i=st; i<n; i++){
        if(!isused[i]){
            arr[k] = num[i];
            isused[i] = 1;
            backtrack(k+1, n);
            isused[i] = 0;
        }
    }
}

int main(void) {
    ios::sync_with_stdio(0);
    cin.tie(0);

    while(1){
        cin >> k;
        if(k==0) break;
        for(int i=0; i<k; i++){
            cin >> num[i];
        }

        backtrack(0, k);
        cout << '\n';
    }

    return 0;
}