#include <iostream>
#include <cstring>
#include <string>
#include <set>
#include <map>
using namespace std;void BuildPatchMatchTable(int *partMatchTable, char *findstr)
{if(findstr == NULL)return;partMatchTable[0] = 0;int sizefind = strlen(findstr);for(int i = 1; i < sizefind; ++i){set<string> preset;string tmppre = "";tmppre = findstr[0];preset.insert(tmppre);for(int j = 1; j < i; ++j){tmppre = tmppre + findstr[j];preset.insert(tmppre);}set<string> postset;string tmppost = "";tmppost = findstr[i];postset.insert(tmppost);for(int j = i - 1; j > 0; --j){tmppost =  findstr[j] + tmppost;postset.insert(tmppost);}set<string> comset;for(set<string>::iterator beg = preset.begin(); beg != preset.end(); ++beg){if(postset.count(*beg) > 0)comset.insert(*beg);}int maxlen = 0;for(set<string>::iterator beg = comset.begin(); beg != comset.end(); ++beg){if((*beg).size() > maxlen)maxlen = (*beg).size();}partMatchTable[i] = maxlen;}
}    int kmp(char *srcstr, char *findstr)
{if(srcstr == NULL || findstr == NULL)return -1;int lensrc = strlen(srcstr);int lenfind = strlen(findstr);int *partMatchTable = new int[lenfind];BuildPatchMatchTable(partMatchTable, findstr);for(int i = 0; i < lenfind; ++i)cout << findstr[i] << "\t" << partMatchTable[i] << endl;int curFind = 0;for(int i = 0; i < lensrc; ){if(findstr[curFind] == srcstr[i]){++i;++curFind;}else{if(curFind == 0)++i;else{int movestep = curFind - partMatchTable[curFind-1];i += movestep;curFind = 0;}}if(curFind == lenfind){delete []partMatchTable;return i - lenfind;}}return -1;delete []partMatchTable;
}
int main()
{char srcStr[] = "bbc abcdab abcdabcdabde";char findStr[] = "abcdabd";cout << "pos:" << kmp(srcStr, findStr) << endl;char srcStr2[] = "bbc abcdab abcdabcdabdezzz";char findStr2[] = "zzz";cout << "pos:" << kmp(srcStr2, findStr2) << endl;char srcStr3[] = "bbc abcdab abcdabcdabde";char findStr3[] = "zzz";cout << "pos:" << kmp(srcStr3, findStr3) << endl;
}