Create pump.cpp

1 files changed, 46 insertions, 0 deletions

diff --git a/2019/December/pump.cpp b/2019/December/pump.cpp
new file mode 100644
index 0000000..20beb76
--- /dev/null
+++ b/2019/December/pump.cpp
@@ -0,0 +1,46 @@
+#include <bits/stdc++.h>
+#define f first
+#define s second
+using namespace std;
+typedef long long ll;
+typedef pair<int, int> ii;
+typedef vector<int> vi;
+typedef vector<ii> vii;
+constexpr int INF = 1e9;
+
+vector<pair<int, ii>> G[1001];
+
+int main() {
+	ifstream cin("pump.in");
+	ofstream cout("pump.out");
+
+	int N, M;
+	cin >> N >> M;
+	while (M--) {
+		int a, b, c, f;
+		cin >> a >> b >> c >> f;
+		G[a].emplace_back(b, ii(c, f));
+		G[b].emplace_back(a, ii(c, f));
+	}
+
+	int ans = 0;
+	for (int i = 1; i <= 1000; ++i) {
+		vi dist(N + 1, INF);
+		dist[1] = 0;
+		priority_queue<ii, vii, greater<ii>> pq;
+		pq.emplace(0, 1);
+		while (!pq.empty()) {
+			int d = pq.top().f, u = pq.top().s;
+			pq.pop();
+			if (d > dist[u]) continue;
+			for (auto& v : G[u]) {
+				if (v.s.s >= i && d + v.s.f < dist[v.f]) {
+					dist[v.f] = d + v.s.f;
+					pq.emplace(dist[v.f], v.f);
+				}
+			}
+		}
+		ans = max((int)1e6 * i / dist[N], ans);
+	}
+	cout << ans << '\n';
+}