Implement StrStr ()

Description:

Implement strStr ().

Returns the index of the first occurrence of needle in haystack, or-1 if needle are not part of haystack.

Code:

vector<int> GetNext (string&t) {size_t n=t.length (); Vector<int>next (n,-1); inti =0, j =-1;  while(I < n1 )    {        if(j = =-1|| T[i] = =T[j]) {            ++i; ++J; Next[i]=J; }        ElseJ=Next[j]; }     for(inti =0; I < next.size (); ++i) cout<<Next[i]; cout<<Endl; returnnext;}intINDEXKMP (string& T,string&w, vector<int>&next) {    inti =0, j =0; intLENGTHT =t.length (); intLENGTHW =w.length ();  while(I < lengtht && J <lengthw) {        if(j = =-1|| T[i] = = W[j])//continue to compare subsequent characters        {            ++i; ++J; }        ElseJ=Next[j]; }    if(J = =lengthw)returnILENGTHW; Else        return-1;} intSTRSTR (stringHaystackstringneedle) {        if(Needle = ="")            return 0; if(Haystack = ="")            return-1; Vector<int>Next; Next=GetNext (needle); returnINDEXKMP (Haystack,needle,next); return-1; }

Implement StrStr ()