Submission #351290

#	Time	Username	Problem	Language	Result	Execution time	Memory
351290		minoum	Flood (IOI07_flood)	C++17	100 / 100	426 ms	32656 KiB

flood

#include<bits/stdc++.h>
 
using namespace std;
typedef long long int ll;
 
const int MAXN = 4e5 + 10;
 
int n, m, h[MAXN], wl[4][MAXN]; //dw[MAXN], up[MAXN], lf[MAXN], ri[MAXN], allw[MAXN];
vector <pair<int,int>> pt, adj[MAXN], ofo, amo, all; //ofo=y,amo=x
 
inline void addedge(){
	for(int i = 0; i < n; i++){
		all.clear();
		for(int j = 0; j < 4; j++) 
			if(wl[j][i] != -1) all.push_back({j, wl[j][i]});
		if(all.empty()) continue;
		sort(all.begin(), all.end()); all.push_back(all[0]);
		for(int j = 0; j < (int)all.size()-1; j++){
			int id = all[j].second, di = all[j].first, id2 = all[j+1].second, di2 = all[j+1].first;
			int t1 = (di==3||di==2), t2 = (di2==3||di2==2); //0->{1,0}  1->{3,2}
			if(t1 && !t2){
				adj[id].push_back({id2,0});
				adj[id2].push_back({id,0});
			}
			if(t1 && t2){
				adj[id].push_back({id2+m,0});
				adj[id2+m].push_back({id,0});
			}
			if(!t1 && !t2){
				adj[id+m].push_back({id2,0});
				adj[id2].push_back({id+m,0});
			}
			if(!t1 && t2){
				adj[id+m].push_back({id2+m,0});
				adj[id2+m].push_back({id+m,0});
			}
		}
	}
	for(int i = 0; i < m; i++){
		adj[i].push_back({i+m,1});
		adj[i+m].push_back({i,1});
	}
	return;
}
 
inline void slv(int r){
	set <pair<int,int>> st; h[r] = 0;
	st.insert({0,r});
	while(!st.empty()){
		int v = st.begin()->second; st.erase(*st.begin());
		for(auto i: adj[v]){
			int u = i.first, ww = i.second;
			if(h[u] > h[v]+ww){
				st.erase({h[u],u});
				h[u] = h[v]+ww;
				st.insert({h[u],u});
			}
		}
	}
	return;
}
 
int main()
{
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
	for(int i = 0; i < MAXN; i++) h[i] = INT_MAX;
	cin >> n;
	for(int i = 0; i < n; i++){
		int xx,yy;
		cin >> xx >> yy;
		pt.push_back({xx,yy});
//		dw[i] = up[i] = lf[i] = ri[i] = -1;
		wl[0][i] = wl[1][i] = wl[2][i] = wl[3][i] = -1;
	}
	cin >> m;
	for(int i = 0; i < m; i++){
		int u, v;
		cin >> u >> v; u--; v--;
		if(pt[u].first==pt[v].first){
			amo.push_back({pt[u].first,i});
			if(pt[u].second > pt[v].second) swap(u,v);
//			dw[u] = i; up[v] = i;
//			all[u].push_back({2,i});
//			all[v].push_back({0,i});
			wl[2][u] = wl[0][v] = i;
		} 
		else{
			ofo.push_back({pt[u].second,i});
			if(pt[u].first > pt[v].first) swap(u,v);
//			ri[u] = i; lf[v] = i;
//			all[u].push_back({1,i});
//			all[v].push_back({3,i});
			wl[1][u] = wl[3][v] = i;
		}
//		allw[u]++; allw[v]++;
//		w.push_back({u,v});
	}
	addedge();
	sort(ofo.begin(), ofo.end());
	sort(amo.begin(), amo.end());
	for(auto i: ofo)
		if(h[i.second] >= INT_MAX) slv(i.second);
	for(auto i: amo)
		if(h[i.second] >= INT_MAX) slv(i.second);
	vector <int> ans;
	for(int i = 0; i < m; i++)
		if(h[i] == h[i+m]) ans.push_back(i);
	cout << (int)ans.size() << '\n';
	for(auto i: ans) cout << i+1 <<'\n';
	return 0; 
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 3 / 3
• Subtask 5: 10 / 10
• Subtask 6: 3 / 3
• Subtask 7: 3 / 3
• Subtask 8: 3 / 3
• Subtask 9: 3 / 3
• Subtask 10: 9 / 9
• Subtask 11: 9 / 9
• Subtask 12: 9 / 9
• Subtask 13: 9 / 9
• Subtask 14: 9 / 9