mzuenni tests

1 files changed, 63 insertions, 0 deletions

diff --git a/content/string/suffixAutomaton.cpp b/content/string/suffixAutomaton.cpp
new file mode 100644
index 0000000..9a68cb3
--- /dev/null
+++ b/content/string/suffixAutomaton.cpp
@@ -0,0 +1,63 @@
+constexpr int ALPHABET_SIZE = 26;
+constexpr char OFFSET = 'a';
+struct SuffixAutomaton {
+	struct State {
+		int len, link = -1;
+		array<int, ALPHABET_SIZE> nxt; // map if large Alphabet
+		State(int l) : len(l) {fill(all(nxt), -1);}
+	};
+
+	vector<State> st = {State(0)};
+	int cur = 0;
+
+	SuffixAutomaton(const string& s) {
+		st.reserve(2 * sz(s));
+		for (auto c : s) extend(c - OFFSET);
+	}
+
+	void extend(int c) {
+		int p = cur;
+		cur = sz(st);
+		st.emplace_back(st[p].len + 1);
+		for (; p != -1 && st[p].nxt[c] < 0; p = st[p].link) {
+			st[p].nxt[c] = cur;
+		}
+		if (p == -1) {
+			st[cur].link = 0;
+		} else {
+			int q = st[p].nxt[c];
+			if (st[p].len + 1 == st[q].len) {
+				st[cur].link = q;
+			} else {
+				st.emplace_back(st[p].len + 1);
+				st.back().link = st[q].link;
+				st.back().nxt = st[q].nxt;
+				for (; p != -1 && st[p].nxt[c] == q; p = st[p].link) {
+					st[p].nxt[c] = sz(st) - 1;
+				}
+				st[q].link = st[cur].link = sz(st) - 1;
+	}}}
+
+	vector<int> calculateTerminals() {
+		vector<int> terminals;
+		for (int p = cur; p != -1; p = st[p].link) {
+			terminals.push_back(p);
+		}
+		return terminals;
+	}
+
+	// Pair with start index (in t) and length of LCS.
+	pair<int, int> longestCommonSubstring(const string& t) {
+		int v = 0, l = 0, best = 0, bestp = -1;
+		for (int i = 0; i < sz(t); i++) {
+			int c = t[i] - OFFSET;
+			while (v > 0 && st[v].nxt[c] < 0) {
+				v = st[v].link;
+				l = st[v].len;
+			}
+			if (st[v].nxt[c] >= 0) v = st[v].nxt[c], l++;
+			if (l > best) best = l, bestp = i;
+		}
+		return {bestp - best + 1, best};
+	}
+};