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-rw-r--r--string/suffixAutomaton.cpp49
1 files changed, 25 insertions, 24 deletions
diff --git a/string/suffixAutomaton.cpp b/string/suffixAutomaton.cpp
index 7f4885c..15265c8 100644
--- a/string/suffixAutomaton.cpp
+++ b/string/suffixAutomaton.cpp
@@ -1,42 +1,42 @@
-#define ALPHABET_SIZE 26
+constexpr char MIN_CHAR = 'a';
+constexpr long long ALPHABET_SIZE = 26;
struct SuffixAutomaton {
struct State {
- int length; int link; int next[ALPHABET_SIZE];
- State() { memset(next, 0, sizeof(next)); }
+ int length, link;
+ vector<int> next;
+ State() : next(ALPHABET_SIZE) {}
};
- static const int MAX_N = 100000; // Maximale Länge des Strings.
- State states[2 * MAX_N];
+ vector<State> states;
int size, last;
- SuffixAutomaton(string &s) { // Laufzeit: O(|s|)
+ SuffixAutomaton(string &s) {
+ states.resize(2 * sz(s));
size = 1; last = 0;
states[0].length = 0;
states[0].link = -1;
- for (auto c : s) extend(c);
+ for (auto c : s) extend(c - MIN_CHAR);
}
- void extend(char c) {
- c -= 'a'; // Werte von c müssen bei 0 beginnen.
+ void extend(int c) {
int current = size++;
states[current].length = states[last].length + 1;
int pos = last;
- while (pos != -1 && !states[pos].next[(int)c]) {
- states[pos].next[(int)c] = current;
+ while (pos != -1 && !states[pos].next[c]) {
+ states[pos].next[c] = current;
pos = states[pos].link;
}
if (pos == -1) states[current].link = 0;
else {
- int q = states[pos].next[(int)c];
+ int q = states[pos].next[c];
if (states[pos].length + 1 == states[q].length) {
states[current].link = q;
} else {
int clone = size++;
states[clone].length = states[pos].length + 1;
states[clone].link = states[q].link;
- memcpy(states[clone].next, states[q].next,
- sizeof(states[q].next));
- while (pos != -1 && states[pos].next[(int)c] == q) {
- states[pos].next[(int)c] = clone;
+ states[clone].next = states[q].next;
+ while (pos != -1 && states[pos].next[c] == q) {
+ states[pos].next[c] = clone;
pos = states[pos].link;
}
states[q].link = states[current].link = clone;
@@ -44,22 +44,23 @@ struct SuffixAutomaton {
last = current;
}
- // Paar mit Startposition und Länge des LCS. Index in Parameter s.
- ii longestCommonSubstring(string &s) { // Laufzeit: O(|s|)
+ // Pair with start index and length of LCS.
+ // Index in parameter t.
+ pair<int, int> longestCommonSubstring(string &t) {
int v = 0, l = 0, best = 0, bestpos = 0;
- for (int i = 0; i < (int)s.size(); i++) {
- int c = s[i] - 'a';
+ for (int i = 0; i < (int)t.size(); i++) {
+ int c = t[i] - MIN_CHAR;
while (v && !states[v].next[c]) {
v = states[v].link;
l = states[v].length;
}
- if (states[v].next[c]) { v = states[v].next[c]; l++; }
- if (l > best) { best = l; bestpos = i; }
+ if (states[v].next[c]) {v = states[v].next[c]; l++;}
+ if (l > best) {best = l; bestpos = i;}
}
- return ii(bestpos - best + 1, best);
+ return {bestpos - best + 1, best};
}
- // Berechnet die Terminale des Automaten.
+ // Returns all terminals of the automaton.
vector<int> calculateTerminals() {
vector<int> terminals;
int pos = last;