Submission #832146

#	Time	Username	Problem	Language	Result	Execution time	Memory
832146		tranxuanbach	Arranging Shoes (IOI19_shoes)	C++17	10 / 100	1096 ms	114044 KiB

shoes

#include "shoes.h"

#include <bits/stdc++.h>
using namespace std;

#define isz(a) ((signed)a.size())

using ll = long long;

const int N = 1e5 + 5;

int n;
int a[N];

namespace subtask12{
	bool check(){
		return n <= 8;
	}

	map <vector <int>, int> dist;

	ll solve(){
		queue <pair <int, vector <int>>> qu;
		auto transition = [&](int d, const vector <int>& state){
			if (not dist.count(state)){
				dist[state] = d;
				qu.emplace(d, state);
			}
		};
		transition(0, vector <int>(a + 1, a + 2 * n + 1));
		while (not qu.empty()){
			auto [d, b] = qu.front(); qu.pop();
			bool ok = true;
			for (int i = 0; i < n; i++){
				if (not (b[2 * i] < 0 and b[2 * i] == -b[2 * i + 1])){
					ok = false;
					break;
				}
			}
			if (ok){
				return d;
			}
			for (int i = 1; i < 2 * n; i++){
				swap(b[i - 1], b[i]);
				transition(d + 1, b);
				swap(b[i - 1], b[i]);
			}
		}
	}
}

ll count_swaps(vector <int> _a){
	n = isz(_a) / 2;
	for (int i = 1; i <= 2 * n; i++){
		a[i] = _a[i - 1];
	}

	if (subtask12::check()){
		return subtask12::solve();
	}
}

Compilation message (stderr)

shoes.cpp: In function 'll subtask12::solve()':
shoes.cpp:23:36: warning: control reaches end of non-void function [-Wreturn-type]
   23 |   queue <pair <int, vector <int>>> qu;
      |                                    ^~
shoes.cpp: In function 'll count_swaps(std::vector<int>)':
shoes.cpp:61:1: warning: control reaches end of non-void function [-Wreturn-type]
   61 | }
      | ^

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15