Add 'I Love Strings' with Aho Corasick

Signed-off-by: Bruno Freitas Tissei <bft15@inf.ufpr.br>

contests/Cadernaveis/UVA10679_aho.cpp

+#include <bits/stdc++.h>
+ 
+#define MAX 1010101
+#define EPS 1e-6
+#define MOD 1000000007
+#define inf 0x3f3f3f3f
+#define llinf 0x3f3f3f3f3f3f3f3f
+ 
+#define fi first
+#define se second
+#define pb push_back
+#define ende '\n'
+ 
+#define all(x) (x).begin(), (x).end()
+#define rall(x) (x).rbegin(), (x).rend()
+#define mset(x, y) memset(&x, (y), sizeof(x))
+ 
+using namespace std; 
+ 
+using ll = long long;
+using ii = pair<int,int>;
+ 
+struct AhoCorasick {
+  struct Node {
+    map<char,int> next;
+    int idx, fail, cnt, hei;
+
+    Node() : idx(-1), fail(0), cnt(0), hei(0) {}
+    int has(char i) { return next.count(i); }
+    int &operator[](char i) { return next[i]; }
+  };
+  
+  vector<int> top;
+  vector<Node> trie;
+
+  AhoCorasick(const vector<string> &v) {
+    trie.pb(Node());
+    build(v);
+    top = preprocess();
+  }
+
+  int insert(const string &s) {
+    int n = 0;
+    for (int i = 0; i < s.size(); n = trie[n][s[i]], ++i)
+      if (!trie[n].has(s[i])) {
+        trie[n][s[i]] = trie.size();
+        trie.pb(Node());
+      }
+    return n;
+  }
+
+  void build(const vector<string> &v) {
+    for (int i = 0; i < v.size(); ++i) {
+      int n = insert(v[i]);
+      trie[n].idx = i;
+    }
+    preprocess();
+  }
+
+  inline int suffix(int v, char c) {
+    while (v != 0 && !trie[v].has(c)) v = trie[v].fail;
+    if (trie[v].has(c)) v = trie[v][c];
+    return v;
+  }
+
+  vector<int> preprocess() {
+    vector<int> Q = { 0 };
+    for (int i = 0; i != Q.size(); ++i) {
+      int u = Q[i];
+      for (auto j : trie[u].next) {
+        trie[j.se].fail = u ? suffix(trie[u].fail, j.fi) : trie[u].fail;
+        Q.pb(j.se);
+      }
+    }
+    return Q;
+  }
+
+  vector<int> match(const string &p) {
+    int u = 0;
+    for (auto i : p) {
+      u = suffix(u, i);
+      trie[u].cnt++;
+    }
+
+    for (int i = top.size() - 1; i >= 0; --i)
+      trie[trie[top[i]].fail].cnt += trie[top[i]].cnt;
+
+    vector<int> ans;
+    for (auto i : trie)
+      if (i.idx != -1 && i.cnt)
+        ans.pb(i.idx);
+
+    sort(all(ans));
+    return ans;
+  }
+};
+ 
+int main() {
+  ios::sync_with_stdio(0);
+  cin.tie(0);
+ 
+  int t; cin >> t;
+  while (t--) {
+    string s; cin >> s;
+    int n; cin >> n;
+    vector<string> v(n);
+    for (auto &i : v) cin >> i;
+   
+    AhoCorasick aho(v);
+    vector<int> ans = aho.match(s);
+   
+    map<string,int> M;
+    for (int i = 0, j = 0; i < n; ++i) {
+      if (j < ans.size() && ans[j] == i) { 
+        M[v[j]] = 1; ++j;
+      } else
+        if (!M[v[j]]) M[v[j]] = 0;
+    }
+
+    for (int i = 0; i < n; ++i)
+      cout << (M[v[i]] ? 'y' : 'n') << ende;
+  }
+ 
+  return 0;
+}