Submission #47643

#	Time	Username	Problem	Language	Result	Execution time	Memory
47643		WA_TLE	Beads and wires (APIO14_beads)	C++14	100 / 100	392 ms	22380 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
vector<pair<llint,llint>>dp;
llint ans=0;
pair<llint,llint>solve(int ter,int per){
	llint ml=-big,fans=0,fsa=-big;
	for(auto it:go[ter]){
		if(it.fir==per){ml=it.sec;continue;}
		auto ret=solve(it.fir,ter);
		fans+=ret.fir;
		maxeq(fsa,ret.sec);
	}
	//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);
	dp[ter]=mp(fans+fhos,ml-fhos);
	return dp[ter];
}
void resol(int ter,int per,llint oans,llint osa){
	llint ml=-big,fans=0;
	pair<llint,int> rsa=mp(-big,-1),rsb=mp(-big,-2);
	for(auto it:go[ter]){
		pair<llint,llint>ret;
		if(it.fir==per){ret=mp(oans,osa);}
		else{ret=dp[it.fir];}
		fans+=ret.fir;
		pair<llint,int>rnow=mp(ret.sec,it.fir);
		if(rsb<rnow){rsb=rnow;}
		if(rsa<rsb){swap(rsa,rsb);}
	}
	maxeq(ans,fans);
	//現在のスコア,上を使うことによるマイナスプラス値
	for(auto it:go[ter]){
		if(it.fir==per){continue;}
		llint fhos=0;
		if(it.fir==rsa.sec){maxeq(fhos,it.sec+rsb.fir);}
		else{maxeq(fhos,it.sec+rsa.fir);}
		resol(it.fir,ter,fans-dp[it.fir].fir+fhos,it.sec-fhos);
	}
}

int main(void){
	int n;cin>>n;
	//if(n>10000){return 0;}
	go.res(n);dp.res(n);
	for(int i=1;i<n;i++){
		int a,b;llint c;
		cin>>a>>b>>c;a--;b--;
		go[a].pub(mp(b,c));
		go[b].pub(mp(a,c));
	}
	solve(0,-1);
	resol(0,-1,0,0);
	cout<<ans<<endl;
	return 0;
}

Compilation message (stderr)

beads.cpp: In function 'void resol(int, int, llint, llint)':
beads.cpp:65:8: warning: unused variable 'ml' [-Wunused-variable]
  llint ml=-big,fans=0;
        ^~

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