2019.10.28 at school

Author: EntropyIncreaser

part2/cf587F.cpp

@@ -0,0 +1,178 @@
+#include <cstdio>
+#include <cstring>
+#include <cstdlib>
+#include <cmath>
+#include <ctime>
+#include <cctype>
+ 
+#include <algorithm>
+#include <tuple>
+#include <random>
+#include <bitset>
+#include <queue>
+#include <functional>
+#include <set>
+#include <map>
+#include <vector>
+#include <chrono>
+#include <iostream>
+#include <limits>
+#include <numeric>
+ 
+#define LOG(FMT...) fprintf(stderr, FMT)
+
+using namespace std;
+
+typedef long long ll;
+typedef unsigned long long ull;
+
+// mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
+ 
+template <class T>
+istream& operator>>(istream& is, vector<T>& v) {
+  for (T& x : v)
+    is >> x;
+  return is;
+}
+ 
+template <class T>
+ostream& operator<<(ostream& os, const vector<T>& v) {
+  if (!v.empty()) {
+    os << v.front();
+    for (int i = 1; i < v.size(); ++i)
+      os << ' ' << v[i];
+  }
+  return os;
+}
+
+const int N = 101010, B = 323;
+
+int n, m, tot, b, vc;
+int vertex[N], len[N];
+int trie[N][26], fail[N], prt[N], dfn[N], dfnr[N];
+vector<pair<int, int>> qry1[N], qry2[N];
+char s[N];
+ll ans[N];
+vector<int> ch[N];
+
+int inb[N], blk[B];
+
+int sub[N];
+ll pre[N];
+
+void dfs(int u) {
+  static int t;
+  dfn[u] = ++t;
+  for (int v : ch[u])
+    dfs(v);
+  dfnr[u] = t;
+}
+
+void dfs2(int u) {
+  for (int v : ch[u]) {
+    dfs2(v);
+    sub[u] += sub[v];
+  }
+}
+
+void change(int k, int x) {
+  for (; k % b != 0; ++k)
+    inb[k] += x;
+  k /= b;
+  for (; k <= b; ++k)
+    blk[k] += x;
+}
+
+int query(int k) {
+  return inb[k] + blk[k / b];
+}
+
+int main() {
+  ios::sync_with_stdio(false);
+  cin.tie(nullptr);
+
+  cin >> n >> m;
+  int rt = ++vc;
+  for (int i = 1; i <= n; ++i) {
+    cin >> (s + 1);
+    len[i] = strlen(s + 1);
+    tot += len[i];
+    int v = rt;
+    for (int j = 1; j <= len[i]; ++j) {
+      if (!trie[v][s[j] - 'a']) {
+        trie[v][s[j] - 'a'] = ++vc;
+        prt[vc] = v;
+      }
+      v = trie[v][s[j] - 'a'];
+    }
+    vertex[i] = v;
+    memset(s + 1, 0, len[i]);
+  }
+  b = sqrt(tot) + 1;
+  for (int i = 1; i <= m; ++i) {
+    int l, r, k;
+    cin >> l >> r >> k;
+    if (len[k] >= b) {
+      qry2[k].emplace_back(l - 1, -i);
+      qry2[k].emplace_back(r, i);
+    } else {
+      qry1[l - 1].emplace_back(k, -i);
+      qry1[r].emplace_back(k, i);
+    }
+  }
+  queue<int> q;
+  for (int i = 0; i < 26; ++i)
+    if (trie[1][i]) {
+      q.push(trie[1][i]);
+      fail[trie[1][i]] = 1;
+    }
+  while (!q.empty()) {
+    int u = q.front(); q.pop();
+    for (int i = 0; i < 26; ++i)
+      if (trie[u][i]) {
+        int p = fail[u];
+        while (p != rt && !trie[p][i])
+          p = fail[p];
+        if (trie[p][i])
+          fail[trie[u][i]] = trie[p][i];
+        else
+          fail[trie[u][i]] = rt;
+        q.push(trie[u][i]);
+      }
+  }
+  for (int i = 2; i <= vc; ++i)
+    ch[fail[i]].push_back(i);
+  dfs(1);
+  for (int i = 1; i <= n; ++i) {
+    change(dfn[vertex[i]], 1);
+    change(dfnr[vertex[i]] + 1, -1);
+    for (const auto& pr : qry1[i]) {
+      int u = vertex[pr.first];
+      if (pr.second < 0)
+        for (; u != rt; u = prt[u])
+          ans[-pr.second] -= query(dfn[u]);
+      else
+        for (; u != rt; u = prt[u])
+          ans[pr.second] += query(dfn[u]);
+    }
+  }
+  for (int i = 1; i <= n; ++i)
+    if (!qry2[i].empty()) {
+      memset(sub, 0, sizeof(sub));
+      int u = vertex[i];
+      for (; u != rt; u = prt[u])
+        sub[u] = 1;
+      dfs2(1);
+      for (int j = 1; j <= n; ++j)
+        pre[j] = pre[j - 1] + sub[vertex[j]];
+      for (const auto& pr : qry2[i])
+        if (pr.second < 0)
+          ans[-pr.second] -= pre[pr.first];
+        else
+          ans[pr.second] += pre[pr.first];
+    }
+  for (int i = 1; i <= m; ++i)
+    cout << ans[i] << '\n';
+
+  return 0;
+}

part2/checklist.md

@@ -137,7 +137,8 @@
   - 随便用埃氏筛过程做几遍容斥即可 $\Theta(x\log\log x)$。
 - [ ] cf585F
 - [ ] cf587D
-- [ ] cf587F
+- [x] cf587F
+  - 按 $k$ 串长度分块。长的 $k \rightarrow l, r$，短的 $l, r\rightarrow k$。
 - [ ] cf590E
 - [ ] cf594E
 - [ ] cf603E