vector数组越界 KMP

#include<string>
#include<stdio.h>
#include<iostream>
#include<vector>
using namespace std;
string s1,s2;
vector<int>f;
void init()
{
    f[0] = 0;
    f[1] = 0;
    int n = s2.size();//n = f.size()后面f[i+1]会越界
    for(int i=1,j=0;i<n;i++){
        j = f[i];
        while(j && s2[i] != s2[j]) j =f[j];
        f[i+1] = s2[j] == s2[i] ?j+1:0; 
    }
}
void find()
{
    int n =s1.size();
    int m = s2.size();
    for(int i=0,j=0;i<n;i++){
        while(j && s1[i] != s2[j]) j = f[j];
        if(s1[i] == s2[j])
        j++;
        if(m == j) printf("%d
",i-m+2);
    }
}
int main()
{
    cin>>s1>>s2;
    f.resize(s2.size()+1);
    init();
    find();
    for(int i=1;i<s2.size()+1;i++)
    printf("%d ",f[i]);
    return 0;
}