Submission #620241

#	Time	Username	Problem	Language	Result	Execution time	Memory
620241		GusterGoose27	Travelling Merchant (APIO17_merchant)	C++11	100 / 100	146 ms	3484 KiB

merchant

#include <bits/stdc++.h>

using namespace std;

typedef pair<int, int> pii;
typedef long long ll;
typedef long double ld;

const int MAXN = 100;
const int MAXK = 1000;
const ll inf = 1e18;
const ld ERROR = 1e-9;
int n, m, k;
vector<pii> edges[MAXN];
ll dist[MAXN][MAXN];
ld bfdist[MAXN];
int val[MAXN][MAXN];
int buy[MAXN][MAXK];
int sell[MAXN][MAXK];

bool neg_cycle(ld ben) {
	fill(bfdist, bfdist+n, inf);
	bfdist[0] = 0;
	bool f = 1;
	for (int i = 0; i < n && f; i++) {
		f = 0;
		for (int a = 0; a < n; a++) {
			for (int b = 0; b < n; b++) {
				ld w = ben*dist[a][b]-val[a][b];
				if (bfdist[b] > bfdist[a]+w+ERROR) {
					bfdist[b] = bfdist[a]+w;
					f = 1;
				}
			}
		}
	}
	return f;
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL);
	cin >> n >> m >> k;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < k; j++) {
			cin >> buy[i][j];
			cin >> sell[i][j];
		}
		fill(dist[i], dist[i]+n, inf);
		dist[i][i] = 0;
	}
	for (int i = 0; i < m; i++) {
		int x, y, w;
		cin >> x >> y >> w;
		x--; y--;
		edges[x].push_back(pii(y, w));
		dist[x][y] = w;
	}
	for (int i = 0; i < n; i++) {
		for (int a = 0; a < n; a++) {
			for (int b = 0; b < n; b++) dist[a][b] = min(dist[a][b], dist[a][i]+dist[i][b]);
		}
	}
	for (int a = 0; a < n; a++) {
		for (int b = 0; b < n; b++) {
			for (int i = 0; i < k; i++) {
				if (buy[a][i] != -1 && sell[b][i] != -1)
					val[a][b] = max(val[a][b], sell[b][i]-buy[a][i]);
			}
		}
	}
	int mn = 0;
	int mx = 1e9;
	while (mx > mn+1) {
		int cur = (mn+mx)/2;
		if (neg_cycle(cur-ERROR)) mn = cur;
		else mx = cur;
	}
	cout << mn << "\n";
}

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