How to determine whether a binary tree is complete?

Question

A complete binary tree is defined as a binary tree in which every level, except possibly the deepest, is completely filled. At deepest level, all nodes must be as far left a

Answer 1

int height (node* tree, int *max, int *min) {

  int lh = 0 , rh = 0 ;
  if ( tree == NULL )
    return 0;
  lh = height (tree->left,max,min) ;
  rh = height (tree->right,max,min) ;
  *max = ((lh>rh) ? lh : rh) + 1 ;
  *min = ((lh>rh) ? rh : lh) + 1 ;
  return *max ;
}

void isCompleteUtil (node* tree, int height, int* finish, int *complete) {
  int lh, rh ;
  if ( tree == NULL )
    return ;
  if ( height == 2 ) {
    if ( *finish ) {
      if ( !*complete )
        return;
      if ( tree->left || tree->right )
        *complete = 0 ;
      return ;
    }
    if ( tree->left == NULL && tree->right != NULL ) {
      *complete = 0 ;
      *finish = 1 ;
    }
    else if ( tree->left == NULL && tree->right == NULL )
      *finish = 1 ;
    return ;
  }
  isCompleteUtil ( tree->left, height-1, finish, complete ) ;
  isCompleteUtil ( tree->right, height-1, finish, complete ) ;
}

int isComplete (node* tree) {
  int max, min, finish=0, complete = 1 ;
  height (tree, &max, &min) ;
  if ( (max-min) >= 2 )
    return 0 ;
  isCompleteUtil (tree, max, &finish, &complete) ;
  return complete ;
}