Submission #49944

#	Time	Username	Problem	Language	Result	Execution time	Memory
49944		tmwilliamlin168	Palembang Bridges (APIO15_bridge)	C++14	100 / 100	79 ms	3888 KiB

bridge

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define pii pair<int, int>
#define fi first
#define se second

const int mxN=1e5;
int k, n, med;
ll ba, a1[mxN+1], a2, bs, ts;
vector<pii> ps;
priority_queue<int> bpq;
priority_queue<int, vector<int>, greater<int>> tpq;

inline void upd(int x) {
	if(x<med)
		bpq.push(x), bs+=x;
	else
		tpq.push(x), ts+=x;
	if(bpq.size()+2<=tpq.size()) {
		bpq.push(med), bs+=med;
		med=tpq.top(), tpq.pop(), ts-=med;
	} else if(bpq.size()>=tpq.size()+2) {
		tpq.push(med), ts+=med;
		med=bpq.top(), bpq.pop(), bs-=med;
	}
}

int main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> k >> n;
	for(int i=0; i<n; ++i) {
		char z1, z2;
		pii pi;
		cin >> z1 >> pi.fi >> z2 >> pi.se;
		if(z1!=z2) {
			ps.push_back(pi);
			++ba;
		} else
			ba+=abs(pi.fi-pi.se);
	}
	sort(ps.begin(), ps.end(), [](const pii &a, const pii &b) {
		return a.fi+a.se<b.fi+b.se;
	});
//	cout << "hi1" << endl;
	for(int i=0; i<ps.size(); ++i) {
		upd(ps[i].fi), upd(ps[i].se);
		a1[i+1]=ts-(ll)tpq.size()*med+((ll)bpq.size()-1)*med-bs;
	}
//	cout << "hi2" << endl;
	a2=a1[ps.size()];
	if(k==1) {
//		cout << ba+a1[3] << endl;
		cout << ba+a2;
		return 0;
	}
//	cout << "hi3" << endl;
	bpq=priority_queue<int>(), tpq=priority_queue<int, vector<int>, greater<int>>();
	med=bs=ts=0;
//	cout << "hi4" << endl;
	for(int i=ps.size()-1; i>0; --i) {
		upd(ps[i].fi), upd(ps[i].se);
		a2=min(a1[i]+ts-(ll)tpq.size()*med+((ll)bpq.size()-1)*med-bs, a2);
	}
	cout << ba+a2;
}

Compilation message (stderr)

bridge.cpp: In function 'int main()':
bridge.cpp:49:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0; i<ps.size(); ++i) {
               ~^~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 14 / 14
• Subtask 3: 9 / 9
• Subtask 4: 32 / 32
• Subtask 5: 37 / 37