#138. 【2020.11.28 NOIP模拟赛 T3】生物

https://sjzezoj.com/submission/71454

S2OJ/138/138.cpp

@@ -0,0 +1,77 @@
+#include <iostream>
+#include <algorithm>
+#include <iterator>
+#include <numeric>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2e5 + 5;
+const int mod = 998244353;
+
+int n, m, fa[N << 1], s[N << 1];
+
+constexpr int binpow(int a, int b, int mod = ::mod) {
+    int res = 1;
+
+    while (b) {
+        if (b & 1) res = static_cast<long long>(res) * a % mod;
+        a = static_cast<long long>(a) * a % mod;
+        b >>= 1;
+    }
+
+    return res;
+}
+
+int find(int x) {
+    return fa[x] == x ? x : find(fa[x]);
+}
+
+int query(int x) {
+    int res = binpow(3, n);
+
+    while (fa[x] != x) {
+        res = static_cast<long long>(res) * s[x] % mod;
+        x = fa[x];
+    }
+
+    return res;
+}
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    cin >> n >> m;
+
+    std::iota(std::begin(fa), std::end(fa), 0);
+    std::fill(std::begin(s), std::end(s), 1);
+
+    for (int i = 1, op; i <= m; i++) {
+        cin >> op;
+
+        if (op == 1) {
+            int u, v;
+
+            cin >> u >> v;
+
+            int x = find(u),
+                y = find(v);
+
+            s[x] = 2 * binpow(3, mod - 2) % mod;
+            s[y] = binpow(3, mod - 2) % mod;
+            fa[x] = n + i;
+            fa[y] = n + i;
+        } else {  // op == 2
+            int u;
+
+            cin >> u;
+
+            cout << query(u) << endl;
+        }
+    }
+
+    return 0;
+}