#1498. 换乘(transfer)

https://sjzezoj.com/submission/55703

S2OJ/1497/1497.cpp

@@ -0,0 +1,71 @@
+#include <iostream>
+#include <chrono>
+#include <map>
+#include <random>
+#include <set>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1e6 + 5;
+
+int n, m, a, b, ans;
+unsigned long long sum[N];
+std::vector<std::pair<int, unsigned long long>> g[N];
+std::map<int, unsigned long long> map;
+std::set<unsigned long long> set;
+
+void dfs(int u, int f, unsigned long long s) {
+    sum[u] = sum[f] ^ s;
+
+    for (auto e : g[u]) {
+        int v = e.first;
+        unsigned long long w = e.second;
+
+        if (v == f) continue;
+
+        dfs(v, u, w);
+    }
+}
+
+signed main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    std::mt19937_64 rand(std::chrono::system_clock::now().time_since_epoch().count());
+
+    cin >> n >> m;
+
+    for (int i = 1; i < n; i++) {
+        int u, v, w;
+
+        cin >> u >> v >> w;
+
+        if (!map.count(w)) map[w] = rand();
+        set.insert(map[w]);
+        g[u].emplace_back(v, map[w]);
+        g[v].emplace_back(u, map[w]);
+    }
+
+    dfs(1, 0, 0);
+
+    cin >> a >> b;
+
+    while (m--) {
+        int x = a % n + 1,
+            y = b % n + 1;
+
+        unsigned long long s = sum[x] ^ sum[y];
+
+        if (s == 0 || set.count(s)) ans++;
+
+        a = static_cast<long long>(a) * 666073 % 1000000007;
+        b = static_cast<long long>(b) * 233 % 998244353;
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}

S2OJ/1498/1498.cpp

@@ -0,0 +1,90 @@
+#include <iostream>
+#include <cstring>
+#include <deque>
+#include <set>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 1000005;
+
+int n, m, id[N], last[N], dist[N];
+bool vis[N];
+std::set<int> cs;
+std::vector<std::pair<int, int>> c[N], g[N];
+
+void bfs() {
+    memset(dist, 0x3f, sizeof(dist));
+
+    std::deque<int> q;
+
+    dist[1] = 0;
+    q.emplace_back(1);
+
+    while (!q.empty()) {
+        int u = q.front();
+        q.pop_front();
+
+        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;
+
+                if (w) q.emplace_back(v);
+                else q.emplace_front(v);
+            }
+        }
+    }
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    for (int i = 1, u, v, c; i <= m; i++) {
+        cin >> u >> v >> c;
+
+        ::c[c].emplace_back(u, v);
+        cs.insert(c);
+    }
+
+    int cnt = n;
+    for (int x : cs) {
+        for (auto e : c[x]) {
+            int u = e.first,
+                v = e.second;
+
+            if (last[u] != x) {
+                last[u] = x;
+                id[u] = ++cnt;
+                g[u].emplace_back(id[u], 1);
+                g[id[u]].emplace_back(u, 0);
+            }
+
+            if (last[v] != x) {
+                last[v] = x;
+                id[v] = ++cnt;
+                g[v].emplace_back(id[v], 1);
+                g[id[v]].emplace_back(v, 0);
+            }
+
+            g[id[u]].emplace_back(id[v], 0);
+            g[id[v]].emplace_back(id[u], 0);
+        }
+    }
+
+    bfs();
+
+    cout << (dist[n] == 0x3f3f3f3f ? -1 : dist[n]) << endl;
+
+    return 0;
+}