Submission #205734

#	Time	Username	Problem	Language	Result	Execution time	Memory
205734		songc	Arranging Tickets (JOI17_arranging_tickets)	C++14	100 / 100	1751 ms	8048 KiB

arranging_tickets

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef pair<int,int> pii;
 
int N, M;
LL A[202020], B[202020], ans;
 
struct Line{
	int l, r, c;
	bool operator<(const Line &t)const{return l < t.l;}
} P[101010];
priority_queue<pii> PQ;
 
bool chk(int t, LL m, LL n){
	int k=1;
	LL x=0;
	for (int i=1; i<=N; i++) B[i] = 0;
	for (int i=1; i<=t; i++){
		LL p=(n+A[i]-m+1)/2-x;
		if (i==t) p=n-x;
		while (P[k].l == i && k <= M){
			if (P[k].r >= t) PQ.push((pii){P[k].r, P[k].c});
			k++;
		}
		if (p>0) x+=p;
		while (p>0){
			if (PQ.empty()) return false;
			pii T = PQ.top();
			PQ.pop();
			if (T.second > p){
				B[T.first] += p;
				T.second -= p, PQ.push(T);
				break;
			}
			else{
				B[T.first] += T.second;
				p -= T.second;
			}
		}
	}
	while (k<=M) {
		B[P[k].l]+=P[k].c, B[P[k].r]-=P[k].c;
		k++;
	}
	while (!PQ.empty()){
		B[t]+=PQ.top().second, B[PQ.top().first]-=PQ.top().second;
		PQ.pop();
	}
	for (int i=t; i<=N; i++){
		B[i] += B[i-1];
		if (B[i] > m) return false;
	}
	return true;
}
 
int main(){
	scanf("%d %d", &N, &M);
	for (int i=1; i<=M; i++){
		scanf("%d %d %d", &P[i].l, &P[i].r, &P[i].c);
		if (P[i].l > P[i].r) swap(P[i].l, P[i].r);
		A[P[i].l] += P[i].c, A[P[i].r] -= P[i].c;
	}
	sort(P+1, P+M+1);
	LL L=0, H=0;
	int l, r;
	for (int i=1; i<=N; i++){
		A[i] += A[i-1];
		if (H < A[i]) l=r=i, H=A[i];
		if (H == A[i]) r=i;
	}
	while (L<=H){
		LL mid=L+H>>1;
		if (chk(l, mid, A[l]-mid) || chk(l, mid, A[l]-mid+1) || chk(r, mid, A[r]-mid) || chk(r, mid, A[r]-mid+1)) H=mid-1, ans=mid;
		else L = mid+1;
	}
	printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

arranging_tickets.cpp: In function 'int main()':
arranging_tickets.cpp:58:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &N, &M);
  ~~~~~^~~~~~~~~~~~~~~~~
arranging_tickets.cpp:60:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d %d", &P[i].l, &P[i].r, &P[i].c);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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