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Submission #408878

# Submission time Handle Problem Language Result Execution time Memory
408878 2021-05-19T18:33:57 Z Jasiekstrz Islands (IOI08_islands) C++17
90 / 100
 1052 ms 131076 KB 
#include<bits/stdc++.h>
#define fi first
#define se second
using namespace std;
const int N=1e6;
vector<int> e[N+10];
int f[N+10];
int l[N+10];
bitset<N+10> vis_fill;
bitset<N+10> vis_s;
bitset<N+10> on_cycle;
vector<int> t;
void dfs_fill(int x)
{
	t.push_back(x);
	vis_fill[x]=true;
	for(auto v:e[x])
	{
		if(!vis_fill[v])
			dfs_fill(v);
	}
	return;
}
pair<long long,long long> dfs_tree(int x)
{
	on_cycle[x]=true;
	pair<long long,long long> ans={0,0};
	for(auto v:e[x])
	{
		if(on_cycle[v])
			continue;
		auto tmp=dfs_tree(v);
		ans.fi=max({ans.fi,tmp.fi,ans.se+tmp.se+(v==f[x] ? l[x]:l[v])});
		ans.se=max(ans.se,tmp.se+(v==f[x] ? l[x]:l[v]));
	}
	ans.fi=max(ans.fi,ans.se);
	return ans;
}
long long solve()
{
	long long ans=0;
	int c;
	for(int i=t[0];true;i=f[i])
	{
		if(vis_s[i])
		{
			c=i;
			break;
		}
		vis_s[i]=true;
	}
	long long l_all=l[c];
	on_cycle[c]=true;
	for(int i=f[c];i!=c;l_all+=l[i],i=f[i])
		on_cycle[i]=true;
	long long mx=0,mn=0;
	int x=c;
	do{
		x=f[x];
		auto ww=dfs_tree(x);
		ans=max(ans,ww.fi);
		ans=max({ans,mx+ww.se,mn+ww.se});
		mx=max(mx,ww.se)+l[x];
		mn=max(mn,ww.se+l_all)-l[x];
	}while(x!=c);
	return ans;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	int n;
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		int a,b;
		cin>>a>>b;
		f[i]=a;
		l[i]=b;
		e[i].emplace_back(a);
		e[a].emplace_back(i);
	}
	long long ans=0;
	for(int i=1;i<=n;i++)
	{
		if(!vis_fill[i])
		{
			t.clear();
			dfs_fill(i);
			ans+=solve();
		}
	}
	cout<<ans<<"\n";
	return 0;
}

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 23756 KB Output is correct
2 Correct 14 ms 23796 KB Output is correct
3 Correct 14 ms 23756 KB Output is correct
4 Correct 14 ms 23756 KB Output is correct
5 Correct 16 ms 23884 KB Output is correct
6 Correct 14 ms 23760 KB Output is correct
7 Correct 15 ms 23756 KB Output is correct
8 Correct 15 ms 23756 KB Output is correct
9 Correct 13 ms 23756 KB Output is correct
10 Correct 14 ms 23756 KB Output is correct
11 Correct 14 ms 23840 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 23884 KB Output is correct
2 Correct 14 ms 23884 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 23820 KB Output is correct
2 Correct 15 ms 24140 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 24508 KB Output is correct
2 Correct 30 ms 26428 KB Output is correct
3 Correct 25 ms 24808 KB Output is correct
4 Correct 19 ms 24300 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 27344 KB Output is correct
2 Correct 52 ms 28996 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 96 ms 34224 KB Output is correct
2 Correct 96 ms 38196 KB Output is correct
3 Correct 123 ms 44188 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 153 ms 40872 KB Output is correct
2 Correct 196 ms 58168 KB Output is correct
3 Correct 219 ms 65528 KB Output is correct
4 Correct 264 ms 77368 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 342 ms 73032 KB Output is correct
2 Correct 773 ms 99152 KB Output is correct
3 Correct 305 ms 56804 KB Output is correct
4 Correct 375 ms 84416 KB Output is correct
5 Correct 390 ms 86200 KB Output is correct
6 Correct 1052 ms 66140 KB Output is correct
7 Correct 407 ms 104272 KB Output is correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 431 ms 131076 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -