Created
December 3, 2020 06:42
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| #include <iostream> | |
| #include <string> | |
| #include <vector> | |
| using namespace std; | |
| vector<int> prefix(string str) { | |
| int n = str.size(); | |
| vector<int> p(n); | |
| p[0] = 0; | |
| for (int i = 1; i < n; i++) { | |
| int q = p[i - 1]; | |
| test: | |
| if (str[i] == str[q]) { | |
| p[i] = q + 1; | |
| } | |
| else { | |
| if (q == 0) { | |
| p[i] = 0; | |
| } | |
| else { | |
| q = p[q - 1]; | |
| goto test; | |
| } | |
| } | |
| } | |
| return p; | |
| } | |
| vector<int> kmp(string pattern, string str) { | |
| int k = 0; | |
| vector<int> p = prefix(pattern); | |
| vector<int> a; | |
| int length = str.size(); | |
| for (int i = 0; i < length; i++) { | |
| while (k > 0 && str[i] != pattern[k]) { | |
| k = p[k - 1]; | |
| } | |
| if (str[i] == pattern[k]) { | |
| k++; | |
| } | |
| if (k == pattern.size()) { | |
| int pos = i - k + 1; | |
| a.push_back(pos); | |
| k = p[k - 1]; | |
| } | |
| } | |
| return a; | |
| } | |
| int main() { | |
| string str = "1213121214121"s; | |
| string pat = "121"s; | |
| vector<int> matches = kmp(pat, str); | |
| for (int m : matches) { | |
| cout << m << endl; | |
| } | |
| } |
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