kmp算法--c++ code

此文旨在記錄Kmp算法，便於以後複習

代碼如下：

#include <iostream>
#include <string>
#include <vector>

using namespace std;

void next_vec(string s1,vector<int> &next)
{
	int k = 0;
	next.push_back(0);

	for (int i = 1; i < s1.size(); i++)
	{
		while (k>0 && s1[i] != s1[k])
			k = next[k-1];

		if (s1[i] == s1[k])
			k++;

		next.push_back(k);
	}
}


void kmp(string s1, string s2)
{
	vector<int> next;
	next_vec(s2, next);

	for (int i = 0, q = 0; i < s1.size(); i++)
	{
		while (q>0 && s2[q] != s1[i])
			q = next[q-1];

		if (s2[q] == s1[i])
			q++;

		if (q == s2.size())
		{
			cout << i - s2.size() + 1 << endl;
			return;
		}
	}
	cout << "no match" << endl;
	return;
}


int main(int argc, char *argv[])
{
	string s1, s2;
	getline(cin, s1);
	getline(cin, s2);


	kmp(s1,s2);

	return 0;


}

參考：

[1]http://blog.csdn.net/v_july_v/article/details/7041827

[2]http://www.cnblogs.com/c-cloud/p/3224788.html

[3]http://www.ruanyifeng.com/blog/2013/05/Knuth%E2%80%93Morris%E2%80%93Pratt_algorithm.html