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Submission #1102757

# Submission time Handle Problem Language Result Execution time Memory
1102757 2024-10-18T19:01:43 Z _rain_ Islands (IOI08_islands) C++14
80 / 100
 521 ms 131072 KB 
#include<bits/stdc++.h>
using namespace std;

#define name "main"
typedef long long ll;
typedef pair<int,int> ii;
#define fi first
#define se second

const int N = (int)1e6;
vector<ii> ke[N+2];
int cost[N+2],gi[N+2],vis[N+2],n,cha[N+2],arr[N+2],sz=0,times=0;
ll dep[N*2+2]={},pre[N*2+2]={},f[N*2+2]={};
bool com[N+2];
void add_edge(int u , int v , int w){
	ke[u].push_back({v,w});
	ke[v].push_back({u,w});
}
void search(int u , int p){
	vis[u] = ++times;
	for (auto& x:ke[u]){
		int v=x.fi,w=x.se;
		if (v==p) continue;
		if (!vis[v]) {
			cha[v]=u;
			gi[v]=w;
			search(v,u);
		}
		else{
			if (vis[v]<vis[u]) continue;
			++sz;
			arr[sz]=v;cost[sz]=w;
			for (; v!=u; v=cha[v]){
				++sz;
				arr[sz]=cha[v];
				cost[sz]=gi[v];
			}
		}
	}
	return ;
}
// the component has at most 1 cycle inside ~
ll mx,ans=0;
int pos,root;
void dfs(int u , int p , ll s){
	if (mx < s){
		mx = s;
		pos = u;
	}
	for (auto& x:ke[u]){
		int v=x.fi,w=x.se;
		if ((com[v]&&v!=root)||v==p) continue;
		dfs(v,u,s+w);
	}
	return;
}

int32_t main(){
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);

	cin>>n;
	for (int i=1; i<=n; ++i){
		int en,l; cin>>en>>l;
		add_edge(i,en,l);
	}
	for (int id=1; id<=n; ++id){
		if (!vis[id]){
			sz = times = 0;
			search(id,id);
			ll addmore = -1;
			for (int i = 1; i <= sz; ++i) com[arr[i]] = true;
			for (int i = 1; i <= sz; ++i){
				mx=pos=root=-1;
				dfs(arr[i],0,0);
				dep[i]=mx;
				root=arr[i];
				dfs(pos,0,0);
				addmore = max(addmore,mx);
				pre[i]=pre[i-1]+cost[i];
			}
			for (int i = sz + 1; i <= sz*2; ++i){
				cost[i] = cost[i-sz];
				dep[i] = dep[i-sz];
				pre[i]=pre[i-1]+cost[i];
			}
			for (int i=1; i<=sz*2; ++i) f[i]=dep[i]-pre[i];
			deque<int> q;
			for (int i = 1; i <= sz*2; ++i){
				while (q.size() && q.front()<i-sz+1) q.pop_front();
				if (q.size()){
					addmore = max(addmore,pre[i]+dep[i]+f[q.front()]);
				}
				while (q.size() && f[q.back()]<=f[i]) q.pop_back();	
				q.push_back(i);
			}
			ans+=addmore;
		}
	}
	cout<<ans;
	exit(0);
}

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 39760 KB Output is correct
2 Correct 6 ms 39960 KB Output is correct
3 Correct 6 ms 40016 KB Output is correct
4 Correct 6 ms 39760 KB Output is correct
5 Correct 7 ms 39760 KB Output is correct
6 Correct 6 ms 39760 KB Output is correct
7 Correct 6 ms 39760 KB Output is correct
8 Correct 6 ms 39760 KB Output is correct
9 Correct 6 ms 39760 KB Output is correct
10 Correct 6 ms 39760 KB Output is correct
11 Correct 7 ms 39760 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 40016 KB Output is correct
2 Correct 6 ms 40016 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 40016 KB Output is correct
2 Correct 7 ms 40272 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 40784 KB Output is correct
2 Correct 19 ms 43060 KB Output is correct
3 Correct 15 ms 40784 KB Output is correct
4 Correct 11 ms 40272 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 44112 KB Output is correct
2 Correct 27 ms 45648 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 51 ms 49528 KB Output is correct
2 Correct 68 ms 59980 KB Output is correct
3 Correct 84 ms 74312 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 111 ms 56172 KB Output is correct
2 Correct 148 ms 92236 KB Output is correct
3 Correct 161 ms 103432 KB Output is correct
4 Correct 206 ms 131072 KB Output is correct

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 202 ms 83368 KB Output is correct
2 Runtime error 521 ms 131072 KB Execution killed with signal 9
3 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 273 ms 131072 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -