NGE of an array

6.cpp

// http://www.geeksforgeeks.org/next-greater-element/
// simple stack logic.

int nge(int a[]){
  vector<int> nge;
  stack<int> stk;
  stk.push(a[0]);
  for(int i=1; i<n; i++){
    int next = a[i];
    while( !stk.empty()){
      if(stk.top() < next){
        nge.push_back(next);
        stk.pop();
      }
    }
    stk.push(next);
  }
  return nge;
}