diff options
Diffstat (limited to 'string/kmp.cpp')
| -rw-r--r-- | string/kmp.cpp | 51 |
1 files changed, 24 insertions, 27 deletions
diff --git a/string/kmp.cpp b/string/kmp.cpp index 6844975..47feac5 100644 --- a/string/kmp.cpp +++ b/string/kmp.cpp @@ -1,30 +1,27 @@ -//Preprocessing Substring sub for KMP-Search -vector<int> kmp_preprocessing(string& sub) { - vector<int> b(sub.size() + 1); - b[0] = -1; - int i = 0, j = -1; - while(i < sub.size()) { - while(j >= 0 && sub[i] != sub[j]) - j = b[j]; - i++; j++; - b[i] = j; - } - return b; +// Laufzeit: O(n + m), n = #Text, m = #Pattern +vector<int> kmp_preprocessing(string &sub) { + vector<int> b(sub.length() + 1); + b[0] = -1; + int i = 0, j = -1; + while (i < (int)sub.length()) { + while (j >= 0 && sub[i] != sub[j]) j = b[j]; + i++; j++; + b[i] = j; + } + return b; } -//Searching after Substring sub in s -vector<int> kmp_search(string& s, string& sub) { - vector<int> pre = kmp_preprocessing(sub); - vector<int> result; - int i = 0, j = -1; - while(i < s.size()) { - while(j >= 0 && s[i] != sub[j]) - j = pre[j]; - i++; j++; - if(j == sub.size()) { - result.push_back(i-j); - j = pre[j]; - } - } - return result; +vector<int> kmp_search(string &s, string &sub) { + vector<int> pre = kmp_preprocessing(sub); + vector<int> result; + int i = 0, j = 0; + while (i < (int)s.length()) { + while (j >= 0 && s[i] != sub[j]) j = pre[j]; + i++; j++; + if (j == (int)sub.length()) { + result.push_back(i - j); + j = pre[j]; + } + } + return result; } |
