uva 122 Trees on the level

#include <iostream>
using namespace std;
#include <string>
#include <set>
#include <algorithm>
struct Node {
string v;
string path;
};
Node nodes[300];
set<string> v_set;
set<string> p_set;
int get_(string s) {
int i=0;
for (i=0;i<s.length();i++)
if (s[i]==',')
return i;
return -1;
}
bool cmp(const Node& a, const Node& b) {
if (a.path.length()!=b.path.length())
return a.path.length()<b.path.length();
return a.path<b.path;
}
int main() {
int flag;
int i,j,k;
string str;

i=0;
flag=1;
v_set.clear();
p_set.clear();
while (cin >> str) {
if (str!="()") {
j=get_(str);
if (j!=-1) {
nodes[i].v=str.substr(1,j-1);
nodes[i].path=str.substr(j+1, str.length()-j-2);
if (nodes[i].v.length()==0)
flag=0;
if (p_set.find(nodes[i].path)!=p_set.end())
flag=0;
else
p_set.insert(nodes[i].path);
i++;
}
}
else {
if (flag==0)
cout << "not complete\n";
else {
sort(nodes, nodes+i, cmp);
p_set.clear();
if (nodes[0].path.length()==0) {
p_set.insert(nodes[0].path);
for (j=1;j<i;j++) {
if (p_set.find(nodes[j].path.substr(0,nodes[j].path.length()-1))==p_set.end())
flag=0;
else
p_set.insert(nodes[j].path);
}
if (flag==0)
cout << "not complete\n";
else {
for (j=0;j<i-1;j++)
cout << nodes[j].v << " ";
cout << nodes[j].v << endl;
}
}
else
cout << "not complete\n";
}
i=0;
p_set.clear();
v_set.clear();
flag=1;
}
}
return 0;
}