1 files changed, 44 insertions, 0 deletions
diff --git a/15/day1/comehome.cpp b/15/day1/comehome.cpp
new file mode 100644
index 0000000..e9c72db
--- /dev/null
+++ b/15/day1/comehome.cpp
@@ -0,0 +1,44 @@
+#include <bits/stdc++.h>
+#define f first
+#define s second
+#define int long long
+using namespace std;
+using ll = long long;
+using ii = pair<int, int>;
+
+ii dist[100001], src[100001];
+vector<ii> G[100001];
+
+signed main() {
+	ios_base::sync_with_stdio(0), cin.tie(0);
+
+	int N, M, K; cin >> N >> M >> K;
+	while (M--) {
+		int A, B, D; cin >> A >> B >> D;
+		G[A].emplace_back(D, B), G[B].emplace_back(D, A);
+	}
+
+	priority_queue<ii, vector<ii>, greater<ii>> pq;
+	memset(dist, '?', sizeof dist);
+	for (int i = 1; i <= K; ++i) dist[i] = ii(0, 0), pq.emplace(0, i);
+	while (pq.size()) {
+		int d = pq.top().f, u = pq.top().s;
+		pq.pop();
+		if (d > dist[u].s) continue;
+		for (auto & p : G[u]) {
+			int d = p.f, v = p.s;
+			if ((dist[u].s + d == dist[v].f && src[v].f == u) || (dist[u].s + d == dist[d].s && src[v].s == u)) continue;
+			if (dist[u].s + d <= dist[v].f) {
+				dist[v].s = dist[v].f, src[v].s = src[v].f;
+				dist[v].f = dist[u].s + d, src[v].f = u;
+				pq.emplace(dist[v].s, v);
+			}
+			else if (dist[u].s + d <= dist[v].s) {
+				dist[v].s = dist[u].s + d, src[v].s = u;
+				pq.emplace(dist[v].s, v);
+			}
+		}
+	}
+
+	cout << (dist[N].s <= 1e18 ? dist[N].s : -1) << '\n';
+}
+\ No newline at end of file