oj.uz

Submission #408927

# Submission time Handle Problem Language Result Execution time Memory
408927 2021-05-19T19:48:23 Z Jasiekstrz Islands (IOI08_islands) C++17
90 / 100
 1036 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;
}
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++)
	{
		cin>>f[i]>>l[i];
		e[i].push_back(f[i]);
		e[f[i]].push_back(i);
	}
	long long ans=0;
	for(int j=1;j<=n;j++)
	{
		if(!vis_fill[j])
		{
			t.clear();
			dfs_fill(j);
			long long ans_s=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_s=max(ans_s,ww.fi);
				ans_s=max({ans_s,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);
			ans+=ans_s;
		}
	}
	cout<<ans<<"\n";
	return 0;
}

Subtask #1
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23756 KB Output is correct
2 Correct 13 ms 23756 KB Output is correct
3 Correct 14 ms 23816 KB Output is correct
4 Correct 13 ms 23732 KB Output is correct
5 Correct 16 ms 23756 KB Output is correct
6 Correct 13 ms 23744 KB Output is correct
7 Correct 13 ms 23748 KB Output is correct
8 Correct 13 ms 23756 KB Output is correct
9 Correct 14 ms 23756 KB Output is correct
10 Correct 13 ms 23804 KB Output is correct
11 Correct 14 ms 23804 KB Output is correct

Subtask #2
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 23824 KB Output is correct
2 Correct 14 ms 23812 KB Output is correct

Subtask #3
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 23944 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 20 ms 24772 KB Output is correct
2 Correct 30 ms 26820 KB Output is correct
3 Correct 24 ms 25088 KB Output is correct
4 Correct 20 ms 24456 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 27936 KB Output is correct
2 Correct 48 ms 29856 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 96 ms 34908 KB Output is correct
2 Correct 96 ms 38912 KB Output is correct
3 Correct 122 ms 44940 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 160 ms 41604 KB Output is correct
2 Correct 198 ms 58940 KB Output is correct
3 Correct 219 ms 66240 KB Output is correct
4 Correct 266 ms 78124 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 337 ms 73808 KB Output is correct
2 Correct 777 ms 100444 KB Output is correct
3 Correct 290 ms 57484 KB Output is correct
4 Correct 384 ms 85228 KB Output is correct
5 Correct 378 ms 86984 KB Output is correct
6 Correct 1036 ms 66912 KB Output is correct
7 Correct 415 ms 105456 KB Output is correct

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 419 ms 131076 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -