제출 #302357

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
302357		Hemimor	Islands (IOI08_islands)	C++14	100 / 100	1360 ms	108508 KiB

islands

#include <algorithm>
#include <iostream>
#include <iomanip>
#include <numeric>
#include <cassert>
#include <vector>
#include <cmath>
#include <queue>
#include <set>
#include <map>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=1e9+7;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

const int M=1000000;
int n,deg[M];
bool vis[M];
vp g[M];
ll res,c[M],d[M];

void f(int v){
	res=0;
	vi a,b;
	vis[v]=1;
	queue<int> q;
	q.push(v);
	while(!q.empty()){
		v=q.front();q.pop();
		a.push_back(v);
		for(auto p:g[v]){
			int u=p.first;
			if(!vis[u]){
				vis[u]=1;
				q.push(u);
			}
		}
	}
	for(auto i:a) if(deg[i]==1) q.push(i);
	while(!q.empty()){
		v=q.front();q.pop();
		deg[v]--;
		ll X=0,Y=0;
		for(auto p:g[v]){
			int u=p.first;
			if(deg[u]){
				deg[u]--;
				if(deg[u]==1) q.push(u);
			}
			else{
				ll t=d[u]+abs(p.second);
				d[v]=max(d[v],t);
				if(t>X){
					Y=X;
					X=t;
				}
				else if(t>Y) Y=t;
			}
		}
		res=max(res,X+Y);
	}
	for(auto i:a) if(deg[i]){
		v=i;
		ll X=0,Y=0;
		for(auto p:g[v]){
			int u=p.first;
			if(!deg[u]){
				ll t=d[u]+abs(p.second);
				d[v]=max(d[v],t);
				if(t>X){
					Y=X;
					X=t;
				}
				else if(t>Y) Y=t;
			}
		}
		res=max(res,X+Y);
	}
	int now=v;
	ll t=0;
	do{
		b.push_back(now);
		c[now]=t;
		for(auto p:g[now]){
			int u=p.first;
			if(p.second>0){
				now=u;
				t+=p.second;
			}
		}
	}while(now!=v);
	ll mx=-INF;
	for(auto i:b){
		res=max(res,c[i]+d[i]+mx);
		mx=max(mx,-c[i]+d[i]);
	}
	mx=-INF;
	for(auto i:b){
		res=max(res,t-c[i]+d[i]+mx);
		mx=max(mx,c[i]+d[i]);
	}
}

int main(){
	scanf("%d",&n);
	for(int u=0;u<n;u++){
		int v,w;
		scanf("%d%d",&v,&w);
		v--;
		g[u].push_back({v,w});
		g[v].push_back({u,-w});
		deg[u]++,deg[v]++;
	}
	ll sum=0;
	for(int i=0;i<n;i++) if(!vis[i]){
		f(i);
		sum+=res;
	}
	printf("%lld\n",sum);
}

컴파일 시 표준 에러 (stderr) 메시지

islands.cpp: In function 'int main()':
islands.cpp:127:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  127 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
islands.cpp:130:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  130 |   scanf("%d%d",&v,&w);
      |   ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 33 / 33
• Subtask 2: 3 / 3
• Subtask 3: 4 / 4
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10