c ++ algoritmo para lograr kmp

#include<string>
#include<iostream>
#include<stdlib.h>
using namespace std;


void buildMatch(string pattern, int *& match){
    int m = pattern.size();
    match = (int*)malloc(m * sizeof(int));
    match[0] = -1;
    int i;
    for(int j = 1; j < m; j++){
        i = match[j-1];
        while((i >= 0) && (pattern[j] != pattern[i+1])){
            i = match[i];
        }
        if(pattern[j] == pattern[i + 1]){
            match[j] = i + 1;
        }else{
            match[j] = -1;
        }

    }

}

int kmp(string str, string pattern, int *match){
    int m = str.size();
    int n = pattern.size();
    int i = 0,j = 0;
    buildMatch(pattern, match);
    while(i < m && j < n){
        if(str[i] == pattern[j]){
            i++;
            j++;
        }else if(j > 0){
            j = match[j-1] + 1;
        }else{
            i++;
        }
    }
    return (j == n)? (i - n) : -1;


}
int main(){
    int * match;
    string str2="abcabcacab";
    string str1 ="dhsuidhauiabcabcacab9jwd";


    //for(int i = 0; i < str2.size(); i++){
       // cout << match[i] << " " ;
   // }
    cout << kmp(str1, str2, match);


}