Submission #424499

#	Time	Username	Problem	Language	Result	Execution time	Memory
424499		milleniumEeee	Chameleon's Love (JOI20_chameleon)	C++17	44 / 100	37 ms	456 KiB

chameleon

#ifndef EVAL
#include "grader.cpp"
#endif
#include "chameleon.h"
#include <bits/stdc++.h>
#define fr first
#define sc second
#define pii pair<int, int>
#define pb push_back
#define szof(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define ll long long
using namespace std;

const int MAXN = 505;

// Query(p) | p is vector<int>
// Answer(a, b)

int n;

bool found[MAXN * 2];
vector <int> cand[MAXN * 2];
vector <int> g[MAXN * 2];
int ans[MAXN * 2];
bool f[MAXN * 2][MAXN * 2];

pii get_para(int x, int y) {
	if (x > y) {
		swap(x, y);
	}
	return {x, y};
}


void too_much_query() {
	for (int i = 1; i <= n * 2; i++) {
		for (int j = 1; j <= n * 2; j++) {
			if (i != j) {
				vector <int> ask = {i, j};
				if (Query(ask) == 1) {
					cand[i].pb(j);
				}
			}
		}
		if (szof(cand[i]) == 1) {
			int x = i, y = cand[i][0];
			ans[x] = y;
			ans[y] = x;
		}
	}
	for (int i = 1; i <= n * 2; i++) {
		if (szof(cand[i]) == 3) {
			int a = cand[i][0];
			int b = cand[i][1];
			int c = cand[i][2];
			int to = -1;
			if (Query({i, a, b}) == 1) {
				f[i][c] = f[c][i] = 1;
				to = c;
			}
			else if (Query({i, a, c}) == 1) {
				f[i][b] = f[b][i] = 1;
				to = b;
			}
			else {
				f[i][a] = f[a][i] = 1;
				to = a;
			}
		}
	}
	for (int i = 1; i <= n * 2; i++) {
		if (!ans[i]) {
			set <int> st;
			for (int el : cand[i]) {
				st.insert(el);
			}
			for (int j = 1; j <= n * 2; j++) {
				if (f[i][j]) {
					st.erase(j);
				}
			}
			int need = *st.begin();
			ans[i] = need;
			ans[need] = i;
		}
	}
	set <pii> omg;
	for (int i = 1; i <= n * 2; i++) {
		omg.insert(get_para(i, ans[i]));
	}
	for (auto [x, y] : omg) {
		Answer(x, y);
	}
}

int find_pos(vector <int> vec, int my_pos) {
	if (szof(vec) == 1) {
		return vec[0];
	}
	int mid = szof(vec) / 2 - 1;
	vector <int> left, right;
	for (int i = 0; i < szof(vec); i++) {
		if (i <= mid) {
			left.pb(vec[i]);
		}
		else {
			right.pb(vec[i]);
		}
	}
	int before = Query(left);
	left.pb(my_pos);
	int after = Query(left);
	left.pop_back();
	if (before == after) {
		return find_pos(left, my_pos);
	} else {
		return find_pos(right, my_pos);
	}
}

void Solve(int N) {
	n = N;
	if (n <= 50) { 
		too_much_query();
	} else {
		for (int i = 1; i <= n * 2; i++) {
			if (found[i]) {
				continue;
			}
			vector <int> vec;
			for (int j = 1; j <= n * 2; j++) {
				if (!found[j] && j != i) {
					vec.pb(j);
				}
			}
			int other = find_pos(vec, i);
			found[i] = found[other] = 1;
			Answer(i, other);
		}
	}
}

Compilation message (stderr)

chameleon.cpp: In function 'void too_much_query()':
chameleon.cpp:57:8: warning: variable 'to' set but not used [-Wunused-but-set-variable]
   57 |    int to = -1;
      |        ^~

• Subtask 1: 4 / 4
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 36