From a3590b78bbbe60ad8a40339f6d33b450bdcebf8d Mon Sep 17 00:00:00 2001
From: Bruno Freitas Tissei <bft15@inf.ufpr.br>
Date: Wed, 8 May 2019 18:41:14 -0300
Subject: [PATCH] Fix kmp
Signed-off-by: Bruno Freitas Tissei <bft15@inf.ufpr.br>
---
algorithms/string/kmp.cpp | 82 ++++++++++++++++++++-------------------
1 file changed, 42 insertions(+), 40 deletions(-)
diff --git a/algorithms/string/kmp.cpp b/algorithms/string/kmp.cpp
index 654f710..76357a3 100644
--- a/algorithms/string/kmp.cpp
+++ b/algorithms/string/kmp.cpp
@@ -5,47 +5,49 @@
/// search -> O(n)
/// Complexity (Space): O(n + m)
-int table[MAX];
-
-/// Builds the table where table[i] is the longest prefix of
-/// patt[0..i] which is
-/// also a sufix of patt[0..i]
-/// @param patt pattern to be found
-void preprocess(string patt) {
- int i = 1, len = 0;
-
- while (i < patt.size()) {
- if (patt[i] == patt[len])
- table[i++] = ++len;
- else if (len)
- len = table[len - 1];
- else
- table[i++] = 0;
+struct KMP {
+ string patt;
+ vector<int> table;
+
+ KMP(string patt) :
+ patt(patt), table(patt.size())
+ { preprocess(); }
+
+ /// Builds the table where table[i] is the longest prefix of
+ /// patt[0..i] that is also a sufix of patt[0..i].
+ void preprocess() {
+ int i = 1, len = 0;
+
+ while (i < patt.size()) {
+ if (patt[i] == patt[len])
+ table[i++] = ++len;
+ else if (len)
+ len = table[len - 1];
+ else
+ table[i++] = 0;
+ }
}
-}
-
-/// Searches for occurrences of patt in txt and add indexes of
-/// matches to occurs
-/// @param patt pattern to be found
-/// @param txt text
-void search(string patt, string txt) {
- int i = 0, j = 0;
- vector<int> occurs;
-
- while (i < txt.size()) {
- if (patt[j] == txt[i])
- i++, j++;
-
- if (j == patt.size()) {
-
- // Pattern found at (i - j)
- occurs.push_back(i - j);
- j = table[j - 1];
- } else if (i < txt.size() && patt[j] != txt[i]) {
- if (j > 0)
+
+ /// Searches for occurrences of patt in txt and return vector
+ /// of the indices of occurrence.
+ /// @param txt text
+ vector<int> search(const string &txt) {
+ int i = 0, j = 0;
+ vector<int> occurs;
+
+ while (i < txt.size()) {
+ if (patt[j] == txt[i])
+ i++, j++;
+
+ if (j == patt.size()) {
+ occurs.push_back(i - j);
j = table[j - 1];
- else
- i++;
+ } else if (i < txt.size() && patt[j] != txt[i]) {
+ if (j > 0) j = table[j - 1];
+ else i++;
+ }
}
+
+ return occurs;
}
-}
+};
--
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