Submission #175981

#	Time	Username	Problem	Language	Result	Execution time	Memory
175981		Saboon	Travelling Merchant (APIO17_merchant)	C++14	0 / 100	1041 ms	2236 KiB

merchant

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const int maxn = 105;
const int maxk = 1005;
const int maxm = 10005;
const ll inf = (ll)1e18;
const ld eps = 0.000000000001;

ll b[maxn][maxk], s[maxn][maxk];
int n, m;
pair<pair<int, int>, ld> e[maxn], E[maxn * maxn];
ld dp[maxn][maxn];
ll c[maxn][maxn];
ld sp[maxn];

bool bellman(){
	for (int i = 1; i <= n; i++)
		sp[i] = 0;
	for (int i = 1; i <= n; i++){
		for (int i = 1; i <= n * n; i++){
			int v = E[i].first.first, u = E[i].first.second;
			ld w = E[i].second;
			w -= eps;
			sp[u] = min(sp[u], sp[v] + w);
		}
	}
	for (int i = 1; i <= n * n; i++){
		int v = E[i].first.first, u = E[i].first.second;
		ld w = E[i].second;
		w -= eps;
		if (sp[u] > sp[v] + w)
			return true;
	}
	return false;
}

bool check(ld x){
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= n; j++)
			dp[i][j] = inf;
	for (int i = 1; i <= m; i++){
		int v = e[i].first.first, u = e[i].first.second;
		ld w = e[i].second;
		dp[v][u] = x * w;
	}
	for (int k = 1; k <= n; k++)
		for (int v = 1; v <= n; v++)
			for (int u = 1; u <= n; u++)
				dp[v][u] = min(dp[v][u], dp[v][k] + dp[k][u]);
	int now = 1;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= n; j++)
			E[now ++] = {{i, j}, dp[i][j] - c[i][j]};
	return bellman();
}

int main() {
	ios::sync_with_stdio(false), cin.tie(0);
	int k;
	cin >> n >> m >> k;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= k; j++)
			cin >> b[i][j] >> s[i][j];
	for (int i = 1; i <= m; i++){
		int v, u, w;
		cin >> v >> u >> w;
		e[i] = {{v, u}, w};
	}
	ll answer = 0;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= n; j++)
			for (int x = 1; x <= k; x++)
				if (b[i][x] != -1 and s[j][x] != -1)
					c[i][j] = max(c[i][j], s[j][x] - b[i][x]);
	ld lo = 0, hi = 1000 * 1000 * 1000 + 1;
	int bs = 100;
	while (bs --){
		ld mid = 0.5 * (lo + hi);
		if (check(mid))
			lo = mid;
		else
			hi = mid;
	}
	cout << lo << endl;
}

Compilation message (stderr)

merchant.cpp: In function 'int main()':
merchant.cpp:71:5: warning: unused variable 'answer' [-Wunused-variable]
  ll answer = 0;
     ^~~~~~

• Subtask 1: 0 / 12
• Subtask 2: 0 / 21
• Subtask 3: 0 / 33
• Subtask 4: 0 / 34