Submission #218623

#	Time	Username	Problem	Language	Result	Execution time	Memory
218623		someone_aa	Bitaro’s Party (JOI18_bitaro)	C++17	7 / 100	2105 ms	203128 KiB

bitaro

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
using namespace std;
const int maxn = 100100;
const int b = 200;

set<pair<int,int> > st[maxn];
vector<int>ig[maxn], g[maxn];
vector<int>order;

int n, m, q;

bool blocked[maxn];
bool visited[maxn];
int dp[maxn];

void dfs(int node) {
	if(visited[node]) return;
	visited[node] = true;

	for(int i:ig[node]) {
		if(!visited[i]) {
			dfs(i);
		}
	}
	order.pb(node);
}

int brute_force(int node) {
	dfs(node);
	reverse(order.begin(), order.end());

	int result = -1;
	for(int i=0;i<order.size();i++) {
		int node=order[i];

		for(int i:g[node]) {
			if(!visited[i]) continue;

			dp[node] = max(dp[node], dp[i] + 1);
		}

		//cout<<node<<": "<<dp[node]<<"\n";

		if(!blocked[node])
			result = max(result, dp[node]);
	}

	memset(dp, 0, sizeof(dp));
	memset(visited,false,sizeof(visited));
	order.clear();

	return result;
}

void preprocess() {
	for(int node=1;node<=n;node++) {
		st[node].insert(mp(0, node));
		map<int, int> dists;
		for(int i:ig[node]) {
			//update st[node] with values from st[i] + 1

			// Possible optimization point, in case of TLE
			for(auto vals:st[i]) {
				dists[vals.second] = max(dists[vals.second], vals.first + 1);
			}
		}

		for(auto i:dists) {
			st[node].insert(mp(i.second, i.first));

			if(st[node].size() > b) st[node].erase(st[node].begin());
		}
	}
}


void solve() {
 	int node, qs, x;
	vector<int>points;
	cin>>node>>qs;
	for(int i=0;i<qs;i++) {
		cin>>x;
		points.pb(x);
		blocked[x] = true;
	}

	if(qs > b) {
		cout<<brute_force(node);
		for(int i:points) blocked[i] = false;
		return;
	}

	int maxtunnels = -1;
	for(auto i:st[node]) {
		if(!blocked[i.second]) maxtunnels = max(maxtunnels, i.first);
	}
	cout<<maxtunnels<<"\n";

	for(int i:points) blocked[i] = false;
}

int main() {
	cin>>n>>m>>q;

	int a, b;
	for(int i=0;i<m;i++) {
		cin>>a>>b;
		g[a].pb(b);
		ig[b].pb(a);
	}

	preprocess();
	while(q--) {
		solve();
	}
}

Compilation message (stderr)

bitaro.cpp: In function 'int brute_force(int)':
bitaro.cpp:36:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<order.size();i++) {
              ~^~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 0 / 7
• Subtask 3: 0 / 86