Submission #47636

#	Time	Username	Problem	Language	Result	Execution time	Memory
47636		WA_TLE	Beads and wires (APIO14_beads)	C++14	0 / 100	2 ms	384 KiB

beads

#include<deque>
#include<queue>
#include<vector>
#include<algorithm>
#include<iostream>
#include<set>
#include<cmath>
#include<tuple>
#include<string>
#include<chrono>
#include<functional>
#include<iterator>
#include<random>
#include<unordered_set>
#include<array>
#include<map>
#include<iomanip>
#include <assert.h>
using namespace std;
typedef long long int llint;
typedef long double lldo;
#define mp make_pair
#define mt make_tuple
#define pub push_back
#define puf push_front
#define pob pop_back
#define pof pop_front
#define fir first
#define sec second
#define res resize
#define ins insert
#define era erase
//cout<<setprecision(20)
//cin.tie(0);
//ios::sync_with_stdio(false);
const llint mod=1000000007;
const llint big=2.19e15+1;
const long double pai=3.141592653589793238462643383279502884197;
const long double eps=1e-15;
template <class T,class U>void mineq(T& a,U b){if(a>b){a=b;}}
template <class T,class U>void maxeq(T& a,U b){if(a<b){a=b;}}
llint gcd(llint a,llint b){if(a%b==0){return b;}else return gcd(b,a%b);}
llint lcm(llint a,llint b){return a/gcd(a,b)*b;}
template<class T> void SO(T& ve){sort(ve.begin(),ve.end());}
template<class T> void REV(T& ve){reverse(ve.begin(),ve.end());}
int LBI(vector<int>&ar,llint in){return lower_bound(ar.begin(),ar.end(),in)-ar.begin();}
int UBI(vector<int>&ar,llint in){return upper_bound(ar.begin(),ar.end(),in)-ar.begin();}
vector<vector<pair<int,llint>>>go;//行先,長さ
tuple<llint,llint,llint>solve(int ter,int per){
	//if(go[ter].size()==1){return mp(0,go[ter][0].sec);}//葉
	llint ml=-big,fans=0;
	pair<llint,int>han=mp(-big,-1),hbn=mp(-big,-1),fsa=mp(-big,-1),fsb=mp(-big,-1);
	//ml my long 自分の親への長さ
	//hans 本線-副線の最大
	//hsa,hsb 自分の子の長さ上位二つ
	//fans 副線だとしたときのスコア
	//fsa その子をとるときの最大の良さ
	for(auto it:go[ter]){
		if(it.fir==per){ml=it.sec;continue;}
		auto ret=solve(it.fir,ter);
		fans+=get<0>(ret);
		maxeq(hbn,mp(get<1>(ret)+it.sec,it.fir));
		if(han<hbn){swap(han,hbn);}
		maxeq(fsb,mp(get<2>(ret),it.fir));
		if(fsa<fsb){swap(fsa,fsb);}
	}
	//現在のスコア,上を使うことによるマイナスプラス値
	llint fhos=max(0LL,ml+fsa.fir);
	llint hbot=0;//異なる二つでの、hans+fsa
	if(han.sec==fsa.sec){hbot=max(han.fir+fsb.fir,hbn.fir+fsa.fir);}
	else{hbot=han.fir+fsa.fir;}
	maxeq(hbot,fsa.fir+fsb.fir);
	maxeq(hbot,0);
	//cerr<<"ter="<<ter<<"ret="<<fans+fhos<<" "<<hbot-fhos<<" "<<ml-fhos<<endl;
	return mt(fans+fhos,hbot-fhos,ml-fhos);
}
int main(void){
	int n;cin>>n;go.res(n);n--;
	while(n--){
		int a,b;llint c;
		cin>>a>>b>>c;a--;b--;
		go[a].pub(mp(b,c));
		go[b].pub(mp(a,c));
	}
	go[0].pub(mp(-1,-big));
	auto rets=solve(0,-1);
	cout<<get<0>(rets)+get<1>(rets)<<endl;
	return 0;
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 15
• Subtask 3: 0 / 29
• Subtask 4: 0 / 43