Suffix Tree

Resources:

Tushar Roy 

CF blog 

stanford.edu-lectures 

 Code library

CP_algorithms 

HackerEarth 

GeeksForGeeks 

blogs 

TMP01-cc implementation 

Implementation:

	////https://codeforces.com/blog/entry/16780
	// topic: suffix_tree
	#include <bits/stdc++.h>
	using namespace std;
	#define INF 1<<30
	#define endl '\n'
	#define maxn 100005
	#define tc printf("Case %d: ", cs)
	#define tcn printf("Case %d:\n", cs);
	#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
	typedef long long ll;
	const double PI = acos(-1.0);
	#define dbg1(x) cerr << #x << " = " << x << endl;
	#define dbg2(x, y) cerr << #x << " = " << x << ", " << #y << " = " << y << endl;
	#define dbg3(x, y, z) cerr << #x << " = " << x << ", " << #y << " = " << y << ", " << #z << " = " << z << endl;
	#define dbg4(w,x, y, z) cerr << #w << " = " << w << ", " <<#x << " = " << x << ", " << #y << " = " << y << ", " << #z << " = " << z << endl;
	template < typename F, typename S >
	ostream& operator << ( ostream& os, const pair< F, S > & p ) {
	return os << "(" << p.first << ", " << p.second << ")";
	}
	template < typename T >
	ostream &operator << ( ostream & os, const vector< T > &v ) {
	os << "{";
	for (auto it = v.begin(); it != v.end(); ++it) {
	if ( it != v.begin() ) os << ", ";
	os << *it;
	}
	return os << "}";
	}
	template < typename T >
	ostream &operator << ( ostream & os, const set< T > &v ) {
	os << "[";
	for (auto it = v.begin(); it != v.end(); ++it) {
	if ( it != v.begin()) os << ", ";
	os << *it;
	}
	return os << "]";
	}
	template < typename F, typename S >
	ostream &operator << ( ostream & os, const map< F, S > &v ) {
	os << "[";
	for (auto it = v.begin(); it != v.end(); ++it) {
	if ( it != v.begin() ) os << ", ";
	os << it -> first << " = " << it -> second ;
	}
	return os << "]";
	}
	#define dbg(args...) do {cerr << #args << " : "; faltu(args); } while(0)
	clock_t tStart = clock();
	#define timeStamp dbg("Execution Time: ", (double)(clock() - tStart)/CLOCKS_PER_SEC)
	void faltu () { cerr << endl; }
	template <typename T>
	void faltu( T a[], int n ) {
	for (int i = 0; i < n; ++i) cerr << a[i] << ' ';
	cerr << endl;
	}
	template <typename T, typename ... hello>
	void faltu( T arg, const hello &... rest) { cerr << arg << ' '; faltu(rest...); }
	// Program showing a policy-based data structure.
	#include <ext/pb_ds/assoc_container.hpp> // Common file
	#include <ext/pb_ds/tree_policy.hpp>
	#include <functional> // for less
	#include <iostream>
	using namespace __gnu_pbds;
	using namespace std;
	// GNU link : https://goo.gl/WVDL6g
	typedef tree<int, null_type, less_equal<int>, rb_tree_tag,
	tree_order_statistics_node_update>
	new_data_set;
	/**___________________________________________________**/
	const int inf = 1e9;
	const int N = 1e5 + 5;
	char s[N];
	unordered_map<char, int> to[N];
	int len[N], f_pos[N], link[N];
	int node, pos;
	int sz = 1, n = 0;
	int make_node(int _pos, int _len)
	{
	f_pos[sz] = _pos;
	len[sz] = _len;
	return sz++;
	}
	void go_edge()
	{
	while (pos > len[to[node][s[n - pos]]]) {
	node = to[node][s[n - pos]];
	pos -= len[node];
	}
	}
	void add_letter(char c)
	{
	s[n++] = c;
	pos++;
	int last = 0;
	while (pos > 0) {
	go_edge();
	int edge = s[n - pos];
	int &v = to[node][edge];
	int t = s[f_pos[v] + pos - 1];
	if (v == 0) {
	v = make_node(n - pos, inf);
	link[last] = node;
	last = 0;
	}
	else if (t == c) {
	link[last] = node;
	return;
	}
	else {
	int u = make_node(f_pos[v], pos - 1);
	to[u][c] = make_node(n - 1, inf);
	to[u][t] = v;
	f_pos[v] += pos - 1;
	len[v] -= pos - 1;
	v = u;
	link[last] = u;
	last = u;
	}
	if (node == 0) pos--;
	else node = link[node];
	}
	}
	int main()
	{
	FASTIO
	///*
	#ifndef ONLINE_JUDGE
	freopen("in.txt", "r", stdin);
	freopen("out.txt", "w", stdout);
	freopen("error.txt", "w", stderr);
	#endif
	//*/
	len[0] = inf;
	string s = "abracadabra";
	int ans = 0;
	for (int i = 0; i < (int)s.size(); i++) {
	add_letter(s[i]);
	}
	for (int i = 1; i < sz; i++) {
	ans += min((int)s.size() - f_pos[i], len[i]);
	}
	cout << ans << endl;
	}

view raw suffixTree.cpp hosted with ❤ by GitHub

 

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