C++实现KMP算法（C风格）

/*
 * Main.cpp
 *
 *  Created on: Oct 7, 2015
 *      Author: chris
 */


#include<iostream>
#include<cstring>

using namespace std;

bool get_next(const char* pat, int*& next)
{
	int len = strlen(pat);
	next = new int[len];
	if(!next) return false;

	next[0] = 0;
	int i = 1, j = 0;
	while(i < len) {
		if(pat[i] == pat[j]) {        // matched.
			++i; ++j;                 // move on.
			next[i] = j;              // record next.
		} else if (j != 0){           // doesn't matched.
			j = next[j];              // back trace.
		} else {                      // nomatched.
			next[i] = 0;
			++i;                      // skip.
		}
	}//while

	return true;
}

enum { INDS_INIT_SIZE = 10, INDS_INC_SIZE = 10};

bool Index_KMP(const char* str, const char *pat, int pos, int*& inds)
{

	int *next = NULL;
	if(!get_next(pat, next))              // prepare.
		return false;

	inds = new int[INDS_INIT_SIZE];
	if(!inds) {
		delete next;
		return false;
	}
	inds[0] = INDS_INIT_SIZE;         // arr size
	inds[1] = 0;                      // num of matched ind

	int i = pos, j = 0;
	int Slen = strlen(str), Plen = strlen(pat);
	while(i < Slen) {
		if(str[i] == pat[j])
		{                             // matched.
			++i; ++j;                 // move on.
			if(j >= Plen)
			{                         // found.
				int ind = i - Plen;

				//record
				if(inds[1] + 2 >= inds[0]) {
					int*temp = new int[inds[0] + INDS_INC_SIZE];
					if(!temp) {
						delete inds;
						delete next;
						return false;
					}

					for(int i = 0; i < inds[0]; ++i)
						temp[i] = inds[i];
					delete inds;
					inds = temp;
					inds[0] += INDS_INC_SIZE;
				}//realloc
				inds[inds[1] + 2] = ind;
				++inds[1];

				j = 0;                // continue.
			}
		} else if(j != 0) {           // back trace.
			j = next[j];
		} else {                      // impossible.
			++i;
		}
	}//while

	delete next;
	return true;
}

int main(void)
{
	string str1, str2;

	while(cin >> str1 >> str2) {
		int* found = NULL;
		if(Index_KMP(str1.c_str(), str2.c_str(), 0, found)){
			int * data = found + 2;
			for(int i = 0; i < found[1]; ++i)
				cout << data[i] << " ";
			cout << endl;

			delete found;
		} else
			cout << "failed." << endl;
	}

	return 0;
}