compressed

#include <cstdio>
#include <map>

using namespace std;

map<int,int> compressed;

int main(){
    int n;

    // read input here

    compressed[-123] = 0;
    compressed[-123123123] = 0;
    compressed[321321] = 0;
    compressed[32132112] = 0;
    compressed[0] = 0;

    // end read input

    int cnt = 0;
    for(map<int,int>::iterator it = compressed.begin(); it != compressed.end(); ++it) it->second = cnt++;

    compressed[-123123123] => 0
    compressed[-123] => 1
    compressed[0] => 2
    compressed[321321] => 3
    compressed[32132112] => 4

    return 0;
}