Hyper Prefix Sets

#include<bits/stdc++.h>

using namespace std;

char s[50005][203];

int mx;

struct node
{
    bool endmark;

    int counter;

    node *next[4];

    node()
    {
        counter = 0;

        endmark = false;

        for(int i=0; i<2; i++)
        {
            next[i] = NULL;
        }
    }

}*root;


void Insert(char *str,int len)
{
    node *curr = root;

    int child = 0;

    for(int i=0; i<len; i++)
    {
        int id = str[i] - '0';

        if(curr->next[id]==NULL)
        {
            curr->next[id] = new node();
        }

        curr = curr->next[id];

        curr->counter++;

        child++;

        mx = max(mx,(child*curr->counter));
    }

    curr->endmark = true;
}

void del(node *curr)
{
    for(int i=0; i<2; i++)
    {
        if(curr->next[i])
        {
            del(curr->next[i]);
        }
    }

    delete(curr);
}

int main()
{
    int num,i,a,test,len;

    scanf("%d",&test);

    while(test--)
    {
        root = new node();

        scanf("%d",&num);

        mx = 0;

        for(i=1; i<=num; i++)
        {
            scanf("%s",s[i]);

            len = strlen(s[i]);

            Insert(s[i],len);
        }

        printf("%d\n",mx);

        del(root);
    }

    return 0;
}