Submission #824537

#	Time	Username	Problem	Language	Result	Execution time	Memory
824537		tomruk	Split the Attractions (IOI19_split)	C++17	0 / 100	123 ms	22328 KiB

split

#include "split.h"
#include <bits/stdc++.h>
#define N 100005
using namespace std;
int par[N];
int sz[N];
vector<int> adj[N];
vector<int> adj2[N];
int sub[N];
int n;
int find(int a){
	if(a == par[a])
		return a;
	return par[a] = find(par[a]);
}
bool merge(int a,int b){
	a = find(a);
	b = find(b);
	if(a == b)
		return 0;
	par[a] = b;
	sz[b] += sz[a];
	return 1;
}
int dfs1(int v,int pr){
	sub[v] = 1;
	int ret = v;
	for(auto u:adj[v]){
		if(u == pr)continue;
		int tmp = dfs1(u,v);
		sub[v] += sub[u];
		if(sub[u] > n/2){
			ret = tmp;
		}
	}
	return ret;
}
vector<int> res;
int need;
int ban = -1;
bool ok[N];
void dfs2(int v,int pr,int col){
	if(!need)
		return;
	res[v] = col;
	need--;
	for(auto u:adj[v]){
		if(u == pr || ok[u])continue;
		dfs2(u,v,col);
	}
}
void dfs3(int v,int pr){
	for(auto u:adj[v]){
		if(u == pr)continue;
		merge(u,v);
		dfs3(u,v);
	}
}
bool vis[N];
void dfs4(int v,int col){
	vis[v] = 1;
	if(!need)
		return;
	res[v] = col;
	need--;
	for(auto u:adj2[v]){
		if(!ok[u] || vis[u])continue;
		dfs2(u,v,col);
	}
}
vector<int> find_split(int _n, int a, int b, int c, vector<int> p, vector<int> q){
	n = _n;
	res.assign(n,0);
	for(int i = 0;i<n;i++){
		par[i] = i;
	}
	for(int i = 0;i<p.size();i++){
		if(merge(p[i],q[i])){
			adj[p[i]].push_back(q[i]);
			adj[q[i]].push_back(p[i]);
		}
		adj2[p[i]].push_back(q[i]);
		adj2[q[i]].push_back(p[i]);
	}
	int cent = dfs1(0,-1);
	dfs1(cent,-1);
	vector<int> v = {a,b,c};
	vector<int> ord = {0,1,2};
	sort(ord.begin(),ord.end(),[&](int a,int b){
		return v[a] < v[b];
	});
	for(int i = 0;i<n;i++){
		par[i] = i;
		sz[i] = 1;
	}
	for(auto u:adj[cent]){
		dfs3(u,cent);
	}
	for(int i = 0;i<p.size();i++){
		if(p[i] == cent || q[i] == cent)continue;
		merge(p[i],q[i]);
		if(sz[find(p[i])] >= v[ord[1]]){
			for(int j = 0;j<n;j++){
				if(find(j) == find(p[i])){
					ok[j] = 1;
				}
			}
			res.assign(n,1 + ord[2]);
			need = v[ord[1]];
			dfs4(p[i],1 + ord[1]);
			need = v[ord[0]];
			dfs2(cent,-1,1 + ord[0]);
			break;
		}
		if(sz[find(p[i])] >= v[ord[0]]){
			for(int j = 0;j<n;j++){
				if(find(j) == find(p[i])){
					ok[j] = 1;
				}
			}
			res.assign(n,1 + ord[2]);
			need = v[ord[0]];
			dfs4(p[i],1 + ord[0]);
			need = v[ord[1]];
			dfs2(cent,-1,1 + ord[1]);
			break;
		}
	}
	if(res[0] == 0){
		for(auto u:adj[cent]){
			if(sz[find(u)] >= v[ord[1]]){
				for(int j = 0;j<n;j++){
					if(find(j) == find(u)){
						ok[j] = 1;
					}
				}
				res.assign(n,1 + ord[2]);
				need = v[ord[1]];
				dfs4(u,1 + ord[1]);
				need = v[ord[0]];
				dfs2(cent,-1,1 + ord[0]);
				break;
			}
			if(sz[find(u)] >= v[ord[0]]){
				for(int j = 0;j<n;j++){
					if(find(j) == find(u)){
						ok[j] = 1;
					}
				}
				res.assign(n,1 + ord[2]);
				need = v[ord[0]];
				dfs4(u,1 + ord[0]);
				need = v[ord[1]];
				dfs2(cent,-1,1 + ord[1]);
				break;
			}
		}
	}
	return res;
}

Compilation message (stderr)

split.cpp: In function 'std::vector<int> find_split(int, int, int, int, std::vector<int>, std::vector<int>)':
split.cpp:77:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   77 |  for(int i = 0;i<p.size();i++){
      |                ~^~~~~~~~~
split.cpp:99:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   99 |  for(int i = 0;i<p.size();i++){
      |                ~^~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 11
• Subtask 3: 0 / 22
• Subtask 4: 0 / 24
• Subtask 5: 0 / 36