#2759. 「JOI 2014 Final」飞天鼠

https://loj.ac/s/1348771

LibreOJ/2759/2759.cpp

@@ -0,0 +1,70 @@
+#include <cstring>
+#include <iostream>
+#include <queue>
+#include <vector>
+
+using std::cin;
+using std::cout;
+using std::endl;
+
+const int N = 100005;
+
+int n, m, x, h[N], nh[N];
+std::vector<std::pair<int, long long>> g[N];
+
+// Dijkstra - Shortest Path
+long long dist[N];
+bool vis[N];
+void dijkstra() {
+    memset(dist, 0x3f, sizeof(dist));
+    dist[1] = 0;
+    std::priority_queue<std::pair<long long, int>, std::vector<std::pair<long long, int>>, std::greater<std::pair<long long, int>>> q;
+    q.push(std::make_pair(0, 1));
+    nh[1] = x;
+    while (!q.empty()) {
+        int u = q.top().second;
+        q.pop();
+        if (vis[u]) continue;
+        vis[u] = true;
+        for (auto e : g[u]) {
+            int v = e.first;
+            long long w = e.second;
+            if (nh[u] - w > h[v]) {  // 到达点的高度大于树顶高度
+                if (dist[v] > dist[u] + nh[u] - h[v]) {
+                    dist[v] = dist[u] + nh[u] - h[v];
+                    nh[v] = h[v];
+                    q.push(std::make_pair(dist[v], v));
+                }
+            } else if (nh[u] - w < 0) {  // 飞行中途会落地
+                if (dist[v] > dist[u] + w - nh[u] + w) {
+                    dist[v] = dist[u] + w - nh[u] + w;
+                    nh[v] = 0;
+                    q.push(std::make_pair(dist[v], v));
+                }
+            } else if (dist[v] > dist[u] + w) {  // 其他情况
+                dist[v] = dist[u] + w;
+                nh[v] = nh[u] - w;
+                q.push(std::make_pair(dist[v], v));
+            }
+        }
+    }
+}
+
+int main() {
+    cin >> n >> m >> x;
+    for (int i = 1; i <= n; i++) {
+        cin >> h[i];
+    }
+    for (int i = 1; i <= m; i++) {
+        int u, v;
+        long long w;
+        cin >> u >> v >> w;
+
+        // 保证飞行中途不落地
+        if (w <= h[u]) g[u].push_back(std::make_pair(v, w));
+        if (w <= h[v]) g[v].push_back(std::make_pair(u, w));
+    }
+    dijkstra();
+    cout << (dist[n] == 0x3f3f3f3f3f3f3f3f ? -1 : dist[n] + h[n] - nh[n]) << endl;
+    return 0;
+}