Submission #415835

#	Time	Username	Problem	Language	Result	Execution time	Memory
415835		alishahali1382	Arranging Tickets (JOI17_arranging_tickets)	C++14	85 / 100	630 ms	15336 KiB

arranging_tickets

#include <bits/stdc++.h>
#pragma GCC optimize ("O2,unroll-loops")
//#pragma GCC optimize("no-stack-protector,fast-math")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<pii, int> piii;
typedef pair<ll, ll> pll;
#define debug(x) cerr<<#x<<'='<<(x)<<endl;
#define debugp(x) cerr<<#x<<"= {"<<(x.first)<<", "<<(x.second)<<"}"<<endl;
#define debug2(x, y) cerr<<"{"<<#x<<", "<<#y<<"} = {"<<(x)<<", "<<(y)<<"}"<<endl;
#define debugv(v) {cerr<<#v<<" : ";for (auto x:v) cerr<<x<<' ';cerr<<endl;}
#define all(x) x.begin(), x.end()
#define pb push_back
#define kill(x) return cout<<x<<'\n', 0;

const int inf=1000000010;
const ll INF=1000000000000001000LL;
const int mod=1000000007;
const int MAXN=200010, LOG=17;

int n, m, k, u, v, x, y, t, a, b;
int A[MAXN], B[MAXN], C[MAXN];
ll ps[MAXN], ans, mx;
vector<pii> vec[MAXN];

struct Fenwick{
	ll fen[MAXN];
	void reset(){
		memset(fen, 0, sizeof(fen));
	}
	void add(int pos, ll val){
		for (; pos<MAXN; pos+=pos&-pos) fen[pos]+=val;
	}
	int get(int pos){
		int res=0;
		for (; pos; pos-=pos&-pos) res+=fen[pos];
		return res;
	}
} fen;
bool Check2(ll ted){
	if (ted>ans) return 0;
	fen.reset();
	fen.add(1, ted);
	for (int i=1; i<n; i++) fen.add(i, ps[i]-ps[i-1]);
	
	priority_queue<pii> pq;
	for (int i=1; i<n; i++){
		for (pii p:vec[i]) pq.push(p);
		ll val=fen.get(i);
//		debug2(i, val)
		while (val>ans){
			if (pq.empty()) return 0;
			pii p=pq.top();
			pq.pop();
			int j=p.first;
			ll cnt=p.second;
			if (j<=i) return 0;
			ll t=min((val-ans+1)/2, cnt);
//			debugp(p)
//			debug(t)
			fen.add(i, -2*t);
			fen.add(j, +2*t);
			val-=2*t;
			ted-=t;
			if (ted<0) return 0;
			if (cnt-=t) pq.push({j, cnt});
		}
	}
	return 1;
}
bool Check(){
	if (mx<=ans) return 1;
	if ((mx+1)/2>ans) return 0;
	if (Check2(mx-ans) || Check2(mx-ans+1)) return 1;
	return 0;
}

int main(){
	ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
	//freopen("input.txt", "r", stdin);
	//freopen("output.txt", "w", stdout);
	cin>>n>>m;
	for (int i=1; i<=m; i++){
		cin>>A[i]>>B[i]>>C[i];
		if (A[i]>B[i]) swap(A[i], B[i]);
		ps[A[i]]+=C[i];
		ps[B[i]]-=C[i];
	}
	for (int i=1; i<=n; i++) ps[i]+=ps[i-1];
	mx=*max_element(ps+1, ps+n);
	int l=0, r=0;
	for (int i=1; i<n; i++) if (ps[i]==mx){
		if (!l) l=i;
		r=i;
	}
	for (int j=1; j<=m; j++) if (A[j]<=l && r<B[j]) vec[A[j]].pb({B[j], C[j]});
	
	ll dwn=0, up=mx;
	while (up-dwn>1){
		ans=(dwn+up)>>1;
		if (Check()) up=ans;
		else dwn=ans;
	}
	cout<<up<<"\n";
	
	return 0;
}
/*
3 3
1 2 1
2 3 1
3 1 1

6 3
1 4 1
2 5 1
3 6 1

5 5
1 3 1
1 3 1
5 3 1
5 2 1
2 5 1

4 4
4 2 1
1 3 1
2 4 1
2 4 1


*/

• Subtask 1: 10 / 10
• Subtask 2: 35 / 35
• Subtask 3: 20 / 20
• Subtask 4: 20 / 20
• Subtask 5: 0 / 15