P1462 通往奥格瑞玛的道路

R54771377

Luogu/problem/P1462/P1462.cpp

@@ -0,0 +1,62 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+int n, m, u, v;
+long long b, w, l, r, mid, ans, f[10005], dist[10005];
+vector<pair<int, long long>> g[10005];
+bool vis[10005];
+
+bool check(int x) {
+    if (f[1] > x) return false;
+    memset(dist, 0x3f, sizeof(dist));
+    memset(vis, 0x00, sizeof(vis));
+    priority_queue<pair<long long, int>> q;
+    dist[1] = 0;
+    q.push(make_pair(0, 1));
+    while (!q.empty()) {
+        auto t = q.top();
+        q.pop();
+        if (vis[t.second]) continue;
+        for (auto i : g[t.second]) {
+            if (f[i.first] > x) continue;
+            if (dist[t.second] + i.second < dist[i.first]) {
+                dist[i.first] = dist[t.second] + i.second;
+                q.push(make_pair(-dist[i.first], i.first));
+                if (i.first == n) return dist[n] < b;
+            }
+        }
+        vis[t.second] = true;
+    }
+    return false;
+}
+
+int main() {
+    cin >> n >> m >> b;
+    for (int i = 1; i <= n; i++) {
+        cin >> f[i];
+        r = max(r, f[i]);
+    }
+    for (int i = 1; i <= m; i++) {
+        cin >> u >> v >> w;
+        g[u].push_back(make_pair(v, w));
+        g[v].push_back(make_pair(u, w));
+    }
+    l = 1;
+    ans = -1;
+    while (l <= r) {
+        mid = l + r >> 1;
+        if (check(mid)) {
+            ans = mid;
+            r = mid - 1;
+        } else {
+            l = mid + 1;
+        }
+    }
+    if (ans == -1) {
+        cout << "AFK" << endl;
+    } else {
+        cout << ans << endl;
+    }
+    return 0;
+}