E - Skiing

https://atcoder.jp/contests/abc237/submissions/35509690

AtCoder/ABC237/E/E.cpp

@@ -0,0 +1,75 @@
+#include <iostream>
+#include <queue>
+#include <utility>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2e5 + 5;
+const long long INF = 0x3f3f3f3f3f3f3f3f;
+
+int n, m, h[N];
+long long dist[N], ans;
+std::vector<std::pair<int, int>> g[N];
+bool vis[N];
+
+void dijkstra() {
+    std::fill_n(dist, N, INF);
+
+    std::priority_queue<
+        std::pair<long long, int>,
+        std::vector<std::pair<long long, int>>,
+        std::greater<>>
+        q;
+
+    q.emplace(0, 1);
+    dist[1] = 0;
+
+    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,
+                w = e.second;
+
+            if (dist[v] > dist[u] + w) {
+                dist[v] = dist[u] + w;
+                q.emplace(dist[v], v);
+            }
+        }
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> h[i];
+    }
+
+    for (int i = 1, u, v; i <= m; i++) {
+        cin >> u >> v;
+
+        g[u].emplace_back(v, std::max(h[v] - h[u], 0));
+        g[v].emplace_back(u, std::max(h[u] - h[v], 0));
+    }
+
+    dijkstra();
+
+    for (int i = 1; i <= n; i++) {
+        ans = std::max(ans, static_cast<long long>(h[1]) - h[i] - dist[i]);
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}