Submission #155691

#	Time	Username	Problem	Language	Result	Execution time	Memory
155691		TadijaSebez	Telegraph (JOI16_telegraph)	C++11	0 / 100	4 ms	2680 KiB

telegraph

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
const int N=100050;
vector<pair<int,int>> E[N];
int a[N],c[N],go[N];
bool 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]),E[a[i]].pb({c[i],i}),sum+=c[i];
	for(int i=1;i<=n;i++)
	{
		sort(E[i].rbegin(),E[i].rend());
		if(E[i].size()) go[E[i][0].second]=i,ans+=E[i][0].first;
	}
	int last=-1;
	for(int i=1;i<=n;i++) if(!was[i])
	{
		int mx=-2e9,j;
        for(j=i;j && !was[j];j=go[j])
		{
			int tmp=E[j].size()?-E[j][0].first:0;
			if(E[j].size()>=2) tmp+=E[j][1].first;
			mx=max(mx,tmp);
			was[j]=1;
		}
		if(j) ans+=mx,last=i;
	}
	if(last==1) printf("0\n");
	else printf("%lld\n",sum-ans);
	return 0;
}

Compilation message (stderr)

telegraph.cpp: In function 'int main()':
telegraph.cpp:12:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%i",&n);
  ~~~~~^~~~~~~~~
telegraph.cpp:14:71: 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]),E[a[i]].pb({c[i],i}),sum+=c[i];
                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 30
• Subtask 3: 0 / 30
• Subtask 4: 0 / 30