KMP算法

void get_next(string S, int* next)
{
	next[0] = 0;//初始化为0
	int j = 0, i = 1;//j前缀末尾,i后缀末尾
	cout << next[0] << " ";
	for (i = 1; i < S.length(); i++)
	{

		while (j > 0 && S[i] != S[j])//不相等情况
		{
			j = next[j - 1];//回溯next数组
		}

		if (S[i] == S[j])//相等情况
		{
			j++;
		}
		next[i] = j;//跟新next数组
		cout << next[i] << " ";
	}
}
void KMP(string S, string T, int next[])
{
	int len = 0, i = 0, j = 0;

	for (i = 0; i < S.size(); i++)
	{
		while (j > 0 && T[j] != S[i])
		{
			j = next[j-1];//j往前回溯
		}//直到匹配到想等的
		if ( S[i] == T[j])
		{
			j++;//相等则加j
			
		}
		
		if (j == T.size())
		{
			
			cout << i - T.size() + 2 << endl;
			j = next[j - 1];
			

		}
	}




}
int main()
{
	string s1, s2;

	
	cin >> s1 >> s2;
	int next[1000] = { 0 };
	next[0] = 0;//初始化为0
	
	int j = 0, i = 1;//j前缀末尾,i后缀末尾
	
	for (i = 1; i < s2.size(); i++)
	{

		while (j > 0 && s2[i] != s2[j])//不相等情况
		{
			j = next[j - 1];//回溯next数组
		}

		if (s2[i] == s2[j])//相等情况
		{
			j++;
		}
		next[i] = j;//跟新next数组

	}
	
	KMP(s1, s2, next);
	//打印next数组
	for (int i = 0; i < s2.size(); i++)
	{
		cout << next[i] << " ";
	}
	return 0;

}