백준 소스코드 [C++] 1039 교환

https://www.acmicpc.net/problem/1039

1039번: 교환

백준 소스코드 [C++] 1039 교환

#include <iostream>
#include <algorithm>
#include <queue>
#include <string>
#include <limits.h>
#include <vector>
#include <math.h>
#include <stack>
#include <bitset>
#include <string.h>
#include <set>
#include <map>
#include <unordered_map>
#include <sstream>
#include <cstdlib>
#include <cassert>
#define all(v) v.begin(), v.end()
#define pii pair<int, int>
#define pli pair<ll, int>
#define make_unique(v) sort(all(v)), v.erase(unique(all(v)), v.end())
typedef long long ll;
using namespace std;

bool chk[1010101][11];
int n, m,SIZE;
int MAX = -1;
void dfs(string s,int k) {
    if (m == k) return;

    for(int i=0;i<SIZE-1;i++)
        for (int j = i+1;j < SIZE;j++) {
            if (s[j] == '0' && i == 0) continue;
            swap(s[j], s[i]);
            if (chk[stoi(s)][k+1] == false) {
                chk[stoi(s)][k+1] = true;
                if(k+1==m)
                    MAX = max(MAX, stoi(s));
                dfs(s, k + 1);
            }
            swap(s[j], s[i]);
        }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    string s;
    cin >> s >> m;
    SIZE = s.length();
    dfs(s,0);

    cout << MAX << '\n';
    return 0;
}