UVA - Phone List (trie tree)

#include<bits/stdc++.h>
using namespace std;
int flag;
int last,cur, len,id;
string str;
struct node
{
    bool endmark;
    int next[13];

} root[100000];
void trie(int cur)
{
    for (int i = 0; i < 10; i++)
        root[cur].next[i] = -1;

    root[cur].endmark=false;
}
void insert()
{
    cur=0;
    len=str.size();
    for (int i = 0; i < len; i++)
    {
        id = str[i] - 48;
        if (root[cur].next[id]==-1)
        {
            root[cur].next[id]=last;
            trie(last++);
            cur = root[cur].next[id];
        }
        else
        {
            cur = root[cur].next[id];
            if(root[cur].endmark==true)
            {
                flag=1;
            }
            if(i==len-1)
                flag = 1;
        }
        if(flag==1)
            break;
    }
    root[cur].endmark = true;
}


int main()
{

    int test;
    cin>>test;
    while(test--)
    {
        flag=0;
        last=1;
        trie(0);
        int n;
        cin>>n;
        for(int i=0; i<n; i++)
        {
            cin>>str;
            insert();
        }
        if(flag==1)
            cout<<"NO"<<endl;
        else
            cout<<"YES"<<endl;
    }
    return 0;
}