DS_KMP模式匹配算法

#include <iostream>
#include <string>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
using namespace std;

bool getNext(string T,int* next);
bool KMP(string T , string S , int *next , int &loc); 

int main(int argc, char** argv) {
	
	string T,S;
	S = "0abbcababcaabaabcabcbc";
	T = "0abaabcabc";
	int* next = new int[10];
	int loc;
	
	getNext(T,next);

	for(int i=1;i<T.length();i++){
		cout<<next[i];
	}
	cout<<"\n";
	if(	KMP(T,S,next,loc) )
		cout<<"\nloc:: "<<loc;
	else
		cout<<"\n-1";
	return 0;
}

bool getNext(string T,int *next){
	next[1] = 0;
	int j = 0;
	int i = 1;

	while( i < T.length()){
		/**
			如果Ti=Tj 则表明
			1到k位置前的串 和 k到j的串相同
			则有 next[j+1] = next[j]+1
			
			如果Ti != Tj 则表明 
			1到k位置的串 和 k到j的串不相同
			则有 next[j+1] = next[ 
		**/ 
		if(j==0 ||T.at(i) == T.at(j) ){
			++i;
			++j;
			next[i] = j	;//如果Ti = Tj 则 next[j+1] = next[j] + 1;
				
		}
		else
			j = next[j];//否则  j = next[j] 
	}
	
}

bool KMP(string T,string S,int *next, int &loc){
	
	int i = 1;
	int j = 1;
	
	while(i<S.length() && j< T.length()){
		if(j ==0 ||S.at(i) == T.at(j)){
			++i;
			++j;
		}else{
			j = next[j];//模式串右移 
			
		}
	}
	if(j = T.length()){
		loc = i - T.length();
		return true;
	}else{
		return false;
	}	
}