Submission #230630

#	Time	Username	Problem	Language	Result	Execution time	Memory
230630		wilwxk	Chameleon's Love (JOI20_chameleon)	C++14	44 / 100	77 ms	536 KiB

chameleon

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

const int MAXN = 1005;
const int LOGN = 9;
int color[MAXN];
vector<int> bad[MAXN], ans[MAXN];
vector<int> comp[2];
int n;

void dfs(int u) {
	for(auto v : ans[u]) {
		if(color[v] != -1) continue;
		color[v] = color[u]^1;
		dfs(v);
	}
}

void separate(int k) {
	for(int i = 1; i <= k; i++) color[i] = -1;
	for(int i = 1; i <= k; i++) {
		if(color[i] != -1) continue;
		color[i] = rand()%2;
		dfs(i);
	}

	comp[0].clear();
	comp[1].clear();
	for(int i = 1; i <= k; i++) comp[color[i]].push_back(i);
}

int bsearch(int u, int k, int l, int r) {
	if(l >= r) return l;
	int x = l;
	vector<int> qv;
	for(int j = LOGN; j >= 0; j--) {
		int ind = x + (1<<j);
		if(ind > r) continue;
		qv.clear();
		for(int i = l+1; i <= ind; i++) qv.push_back(comp[k][i]);
		qv.push_back(u);
		// for(auto a : qv) printf("%d ", a); cout << endl;
		// printf("q %d / %d %d %d %d\n", ind, u, k, l, r);
		if(Query(qv) == qv.size()) x = ind;
	}
	return x;
}

void Solve(int N) {
	n = 2*N;

	comp[0].push_back(1);

	for(int u = 2; u <= n; u++) {

		separate(u-1);

		int cnt = 0;
		for(int k = 0; k < 2; k++) {

			int l = -1; int r = comp[k].size()-1;

			for(int kk = 0; kk < 3; kk++) {
				if(cnt == 3) break;
				int ind = bsearch(u, k, l, r);
				if(ind == r) break;

				ans[u].push_back(comp[k][ind+1]);
				ans[comp[k][ind+1]].push_back(u);
				// printf("connect %d %d\n", u, comp[k][ind+1]);

				cnt++;
				l = ind+1;
			}
			
		}
	}


	for(int u = 1; u <= n; u++) {
		if(ans[u].size() == 1) continue;
		else {
			if(Query({u, ans[u][0], ans[u][1]}) == 1) {
				bad[ans[u][2]].push_back(u);
				bad[u].push_back(ans[u][2]);
			}
			else if(Query({u, ans[u][1], ans[u][2]}) == 1) {
				bad[ans[u][0]].push_back(u);
				bad[u].push_back(ans[u][0]);
			}
			else {
				bad[ans[u][1]].push_back(u);
				bad[u].push_back(ans[u][1]);
			}
		}
	}

	for(int u = 1; u <= n; u++) {
		if(color[u] == 2) continue;

		int x;
		if(ans[u].size() == 1) {
			x = ans[u][0];
		}
		else {
			for(int k = 0; k < 3; k++) {
				if(ans[u][k] != bad[u][0] && ans[u][k] != bad[u][1]) {
					x = ans[u][k];
				}
			}
		}
		
		Answer(u, x);
		color[u] = color[x] = 2;
	}
}

Compilation message (stderr)

chameleon.cpp: In function 'int bsearch(int, int, int, int)':
chameleon.cpp:45:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(Query(qv) == qv.size()) x = ind;
      ~~~~~~~~~~^~~~~~~~~~~~
chameleon.cpp: In function 'void Solve(int)':
chameleon.cpp:115:23: warning: 'x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   color[u] = color[x] = 2;
              ~~~~~~~~~^~~

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