Submission #289760

#	Time	Username	Problem	Language	Result	Execution time	Memory
289760		wwdd	Travelling Merchant (APIO17_merchant)	C++14	100 / 100	119 ms	4344 KiB

merchant

// i don't understand
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INFL = 2e18;
const int MN = 105;
const int MK = 1010;
ll am[MN][MN];
ll pr[MN][MN];
ll ro[MN][MN];
ll bro[MN][MK],slo[MN][MK];
int main() {
	ios::sync_with_stdio(0);cin.tie(0);
	ll n,m,ks;
	cin >> n >> m >> ks;
	for(int i=0;i<n;i++) {
		for(int j=0;j<n;j++) {
			am[i][j] = INFL;
		}
	}
	for(int i=0;i<n;i++) {
		for(int j=0;j<ks;j++) {
			cin >> bro[i][j] >> slo[i][j];
		}
	}
	for(int i=0;i<m;i++) {
		ll a,b,c;
		cin >> a >> b >> c;
		a--;b--;
		am[a][b] = c;
	}
	for(int k=0;k<n;k++) {
		for(int i=0;i<n;i++) {
			for(int j=0;j<n;j++) {
				am[i][j] = min(am[i][j],am[i][k]+am[k][j]);
			}
		}
	}
	memset(pr,0,sizeof(pr));
	for(int i=0;i<n;i++) {
		for(int j=0;j<n;j++) {
			for(int k=0;k<ks;k++) {
				if(slo[j][k] == -1) {continue;}
				if(bro[i][k] == -1) {continue;}
				pr[i][j] = max(pr[i][j],slo[j][k]-bro[i][k]);
			}
		}
	}
	ll st = 1,ed = 1e9+2;
	ll ls = 0;
	while(st <= ed) {
		ll md = (st+ed)/2;
		for(int i=0;i<n;i++) {
			for(int j=0;j<n;j++) {
				if(i == j) {
					ro[i][j] = -1;
				} else if(am[i][j] == INFL) {
					ro[i][j] = -INFL;
				} else {
					ro[i][j] = pr[i][j]-md*am[i][j];
				}
			}
		}
		for(int k=0;k<n;k++) {
			for(int i=0;i<n;i++) {
				for(int j=0;j<n;j++) {
					ro[i][j] = max(ro[i][j],ro[i][k]+ro[k][j]);
					ro[i][j] = min(ro[i][j],INFL);
				}
			}
		}
		bool lol = false;
		for(int i=0;i<n;i++) {
			if(ro[i][i] >= 0) {
				lol = true;break;
			}
		}
		if(lol) {
			ls = md;
			st = md+1;
		} else {
			ed = md-1;
		}
	}
	cout << ls << '\n';
}

• Subtask 1: 12 / 12
• Subtask 2: 21 / 21
• Subtask 3: 33 / 33
• Subtask 4: 34 / 34