[Spoj] STRMATCH - Match me if you can

Author            : Dipu Kumar Mohanto 
                    CSE, Batch - 6
                    BRUR.
Problem Statement : STRMATCH - Match me if you can
Source            : Spoj
Category          : String
Algorithm         : Aho-Corasick Algorithm
Verdict           : Accepted

#include "bits/stdc++.h"
 
using namespace std;
 
#define FI              freopen("in.txt", "r", stdin)
#define FO              freopen("out.txt", "w", stdout)
#define FAST            ios_base::sync_with_stdio(false), cin.tie(NULL), cout.tie(NULL)
 
#define FOR(i, n)       for (int i = 1; i <= n; i++)
#define For(i, n)       for (int i = 0; i < n; i++)
#define ROF(i, n)       for (int i = n; i >= 1; i--)
#define Rof(i, n)       for (int i = n-1; i >= 0; i--)
#define FORI(i, n)      for (auto i : n)
 
#define ll              long long
#define ull             unsigned long long
#define vi              vector <int>
#define vl              vector <ll>
#define pii             pair <int, int>
#define pll             pair <ll, ll>
#define mk              make_pair
#define ff              first
#define ss              second
#define eb              emplace_back
#define em              emplace
#define pb              push_back
#define ppb             pop_back
#define All(a)          a.begin(), a.end()
#define memo(a, b)      memset(a, b, sizeof a)
#define Sort(a)         sort(All(a))
#define ED(a)           Sort(a), a.erase(unique(All(a)), a.end())
#define rev(a)          reverse(All(a))
#define sz(a)           (int)a.size()
#define max3(a, b, c)   max(a, max(b, c))
#define min3(a, b, c)   min(a, min(b, c))
#define maxAll(a)       *max_element(All(a))
#define minAll(a)       *min_element(All(a))
#define allUpper(a)     transform(All(a), a.begin(), :: toupper)
#define allLower(a)     transform(All(a), a.begin(), :: tolower)
#define endl            '\n'
#define nl              puts("")
#define ub              upper_bound
#define lb              lower_bound
#define Exp             exp(1.0)
#define PIE             2*acos(0.0)
#define Sin(a)          sin(((a)*PIE)/180.0)
#define EPS             1e-9
 
#include "ext/pb_ds/assoc_container.hpp"
#include "ext/pb_ds/tree_policy.hpp"
using namespace __gnu_pbds;
 
template <typename T> using orderset = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;
 
#include "ext/rope"
using namespace __gnu_cxx;
 
// rope <int> Rope;
 
// int dr[] = {1, -1, 0, 0}; // 4 Direction
// int dc[] = {0, 0, 1, -1};
// int dr[] = {0, 0, 1, -1, 1, 1, -1, -1}; // 8 Direction
// int dc[] = {1, -1, 0, 0, 1, -1, 1, -1};
// int dr[] = {-1, 1, -2, -2, -1, 1, 2, 2}; // knight Moves
// int dc[] = {-2, -2, -1, 1, 2, 2, 1, -1};
 
#define trace1(x)                           cerr << #x << ": " << x << endl;
#define trace2(x, y)                        cerr << #x << ": " << x << " | " << #y << ": " << y << endl;
#define trace3(x, y, z)                     cerr << #x << ": " << x << " | " << #y << ": " << y << " | " << #z << ": " << z << endl;
#define trace4(a, b, c, d)                  cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << endl;
#define trace5(a, b, c, d, e)               cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << " | " << #e << ": " << e << endl;
#define trace6(a, b, c, d, e, f)            cerr << #a << ": " << a << " | " << #b << ": " << b << " | " << #c << ": " << c << " | " << #d << ": " << d << " | " << #e << ": " << e << " | " << #f << ": " << f << endl;
 
inline int setbit(int mask, int pos)        { return mask |= (1 << pos); }
inline int resetbit(int mask, int pos)      { return mask &= ~(1 << pos); }
inline int togglebit(int mask, int pos)     { return mask ^= (1 << pos); }
inline bool checkbit(int mask, int pos)     { return (bool)(mask & (1 << pos)); }
 
#define popcount(mask)                       __builtin_popcount(mask) // count set bit
#define popcountLL(mask)                     __builtin_popcountll(mask) // for long long
 
inline int read()                           { int a; scanf("%d", &a); return a; }
inline ll readLL()                          { ll a; scanf("%lld", &a); return a; }
inline double readDD()                      { double a; scanf("%lf", &a); return a; }
 
template <typename T> string toString(T num) { stringstream ss; ss << num; return ss.str(); }
int toInt(string s)                          { int num; istringstream iss(s); iss >> num; return num;  }
ll toLLong(string s)                         { ll num; istringstream iss(s); iss >> num; return num; }
 
#define inf             123456789
#define mod             1000000007
 
static const int maxn = 500000 + 5;
static const int logn = 18;
 
int tLen, tQuery;
string text, dictinary[maxn];
 
struct node
{
    int cnt;
    bool vis;
    vector < node * > bpin;  // back pointer in
    node *next[150];
    node()
    {
        cnt = 0;
        vis = false;
        bpin.clear();
        for (int i = 1; i < 150; i++) next[i] = nullptr;
    }
    ~node()
    {
        for (int i = 1; i < 150; i++)
        {
            if (next[i] && next[i] != this) delete next[i];
        }
    }
} *root;
 
inline void build_trie()
{
    root = new node();
    for (int i = 0; i < tQuery; i++)
    {
        node *p = root;
        for (char ch : dictinary[i])
        {
            int v = ch - '0';
            if (!p->next[v]) p->next[v] = new node();
            p = p->next[v];
        }
    }
    queue < node * > PQ;
    node *p = root;
    for (int i = 1; i < 150; i++)
    {
        if (!p->next[i])
        {
              p->next[i] = root;
        }
        else
        {
            PQ.push(p->next[i]);
            p->next[i]->next[0] = root;     // back pointer
        }
    }
    while (!PQ.empty())
    {
        node *u = PQ.front(); PQ.pop();
        for (int i = 1; i < 150; i++)
        {
            if (u->next[i] == nullptr) continue;
            node *v = u->next[i];
            node *w = u->next[0];
            while (!w->next[i]) w = w->next[0];
            v->next[0] = w->next[i];
            w->next[i]->bpin.push_back(v);
            PQ.push(v);
        }
    }
}
 
 
inline void aho_corasick()
{
    node *p = root;
    for (char ch : text)
    {
        int v = ch - '0';
        while (!p->next[v]) p = p->next[0];
        p = p->next[v];
        p->cnt++;
    }
}
 
inline int dfs(node *p)
{
    if (p->vis) return p->cnt;
    p->vis = true;
    for (auto it : p->bpin) p->cnt += dfs(it);
    return p->cnt;
}
 
int main()
{
//    FI;
    FAST;
 
    cin >> tLen >> tQuery;
    cin >> text;
    for (int q = 0; q < tQuery; q++) cin >> dictinary[q];
    build_trie();
    aho_corasick();
    for (int q = 0; q < tQuery; q++)
    {
        node *p = root;
        for (char ch : dictinary[q])
        {
            int v = ch - '0';
            p = p->next[v];
        }
        cout << dfs(p) << endl;
    }
    delete root;
}