codeforce round 575

Author: seunghyukcho

Codeforces/Codeforces Round/575/.vscode/settings.json

@@ -0,0 +1,6 @@
+{
+    "files.associations": {
+        "queue": "cpp",
+        "utility": "cpp"
+    }
+}

Codeforces/Codeforces Round/575/F.cpp

@@ -0,0 +1,70 @@
+#include <iostream>
+#include <algorithm>
+#include <queue>
+#include <vector>
+
+using namespace std;
+
+typedef long long ll;
+typedef pair<int, int> pr;
+
+priority_queue<ll> ans;
+int n, m, k;
+vector<pr> graph[200002];
+
+void dijkstra(int start)
+{
+    int times = k + 1;
+    priority_queue<pair<ll, int> > pq;
+    vector<ll> dist(n + 1, -1);
+
+    pq.push({ 0, start });
+    dist[start] = 0;
+
+    while(!pq.empty() && times)
+    {
+        ll d = -pq.top().first;
+        int here = pq.top().second;
+        pq.pop();
+
+        if(d > dist[here]) continue;
+        times--;
+
+        if(here > start) 
+        {
+            ans.push(d);
+            if(ans.size() > k) ans.pop();
+        }
+
+        for(pr edge : graph[here])
+        {
+            int next = edge.first;
+            ll newDist = d + edge.second;
+
+            if(dist[next] == -1 || dist[next] > newDist)
+            {
+                dist[next] = newDist;
+                pq.push({ -newDist, next });
+            }
+        }
+    }
+}
+
+int main()
+{
+    ios::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    cin >> n >> m >> k;
+    for(int i = 0; i < m; i++)
+    {
+        int x, y, w;
+        cin >> x >> y >> w;
+        graph[x].push_back({ y, w });
+        graph[y].push_back({ x, w });
+    }
+
+    for(int i = 1; i <= n; i++) dijkstra(i);
+
+    cout << ans.top() << '\n';
+}