Submission #157403

#	Time	Username	Problem	Language	Result	Execution time	Memory
157403		TadijaSebez	Telegraph (JOI16_telegraph)	C++11	100 / 100	41 ms	3960 KiB

telegraph

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
const int N=100050;
int a[N],c[N],mx1[N],mx2[N];
int was[N];
int main()
{
	int n;
	scanf("%i",&n);
	ll sum=0,ans=0;
	for(int i=1;i<=n;i++) scanf("%i %i",&a[i],&c[i]),sum+=c[i];
	for(int i=1;i<=n;i++) if(was[i]==0)
	{
		int j;
		for(j=i;was[j]==0;j=a[j]) was[j]=i;
		if(was[j]==i)
		{
			int cnt=0;
			for(;was[j]!=-1;j=a[j]) was[j]=-1,cnt++;
			if(cnt==n) return 0*printf("0\n");
		}
	}
	for(int i=1;i<=n;i++)
	{
		mx1[a[i]]=max(mx1[a[i]],c[i]);
		if(was[i]!=-1) mx2[a[i]]=max(mx2[a[i]],c[i]);
	}
	for(int i=1;i<=n;i++) ans+=mx1[i];
	for(int i=1;i<=n;i++) if(was[i]==-1)
	{
		int best=-2e9;
		for(int j=i;was[j]==-1;j=a[j])
		{
			best=max(best,mx2[j]-mx1[j]);
			was[j]=-2;
		}
		ans+=best;
	}
	printf("%lld\n",sum-ans);
	return 0;
}

Compilation message (stderr)

telegraph.cpp: In function 'int main()':
telegraph.cpp:11:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i",&n);
  ~~~~~^~~~~~~~~
telegraph.cpp:13:50: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1;i<=n;i++) scanf("%i %i",&a[i],&c[i]),sum+=c[i];
                        ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 30 / 30
• Subtask 3: 30 / 30
• Subtask 4: 30 / 30