#1604. 【2022.10.5 联考】骑车（bicycle）

https://sjzezoj.com/submission/59585

S2OJ/1604/1604.cpp

@@ -0,0 +1,106 @@
+#include <iostream>
+#include <algorithm>
+#include <array>
+#include <functional>
+#include <limits>
+#include <queue>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e5 + 5;
+
+int n, m;
+long long s, alt[N];
+std::vector<long long> alts;
+std::vector<std::pair<int, long long>> g[N];
+std::array<bool, N> vis;
+std::array<long long, N> dist;
+
+void dijkstra(long long limit) {
+    std::fill(vis.begin(), vis.end(), false);
+    std::fill(dist.begin(), dist.end(), std::numeric_limits<long long>::max() / 3);
+
+    std::priority_queue<std::pair<long long, int>, std::vector<std::pair<int, int>>, std::greater<std::pair<int, int>>> 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;
+            long long w = e.second;
+
+            if (dist[v] > dist[u] + w && alt[v] - alt[u] <= limit) {
+                dist[v] = dist[u] + w;
+                q.emplace(dist[v], v);
+            }
+        }
+    }
+}
+
+bool check(int x) {
+    dijkstra(alts[x]);
+
+    return dist[n] <= s;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m >> s;
+
+    for (int i = 1; i <= n; i++) {
+        cin >> alt[i];
+    }
+
+    for (int i = 1; i <= m; i++) {
+        int u, v;
+        long long w;
+
+        cin >> u >> v >> w;
+
+        g[u].emplace_back(v, w);
+        alts.emplace_back(alt[v] - alt[u]);
+
+        g[v].emplace_back(u, w);
+        alts.emplace_back(alt[u] - alt[v]);
+    }
+
+    std::sort(alts.begin(), alts.end());
+    alts.erase(std::unique(alts.begin(), alts.end()), alts.end());
+
+    int l = 0,
+        r = alts.size() - 1,
+        res = alts.size();
+
+    while (l <= r) {
+        int mid = l + r >> 1;
+
+        if (check(mid)) {
+            r = mid - 1;
+            res = mid;
+        } else {
+            l = mid + 1;
+        }
+    }
+
+    if (res == alts.size()) {
+        cout << "NO" << endl;
+    } else {
+        cout << alts[res] << endl;
+    }
+
+    return 0;
+}