UCV2013J  Valences
Mr. White has found a way to maximize the purity of crystals based on certain chemical compounds. He has observed that each compound is made of molecules that are linked together following the structure of a complete binary tree where every level, except possibly the last, is completely filled, and all nodes are as far left as possible. Each node of the tree stores the valence of a molecule and is represented as an integer number. Mr. White uses an electronic microscope that dumps the molecule structure as a stream of integer numbers and would like to have your help on automatically obtaining the total valence of only the leaves of the given tree. For example, the sequence 432603 represents the tree shown in the figure and the total valence of the leaves is 9.
Input
The input contains several test cases, each one corresponding to a particular compound. Each test case consists of a single line starting with an integer N (1 <= N <= 1000000), followed by N integer numbers Vi representing the valences of each molecule separated by blank spaces (0 <= Vi <= 100).
The end of input is indicated by a test case with N = 0.
Output
For each compound output a single line with the sum of the valences of the leaves of the tree.
Example
Input: 6 4 3 2 6 0 3
7 1 1 1 2 1 2 1
0 Output: 9
6
hide comments
trhgquan:
20200129 05:52:19
My 50th. Basics of tree give you logic between tree leaves and number of nodes. 

pandey101299:
20190416 15:22:33
easy one my 100th


markaman:
20181223 05:55:18
think simple it will work don't afraid of tree:) 

rohit659:
20170528 21:11:35
Easy One!!


adichd123:
20160728 14:09:56
Last edit: 20161101 14:20:16 

mkfeuhrer:
20160728 07:55:54
n/2 simple work :) 

minhthai:
20160204 05:51:38
remember heap ? :) 

Tony Stark:
20150507 21:01:27
ok got it! Last edit: 20150507 21:03:46 

Asheesh Pathak:
20150401 19:12:51
Just leave first n/2 nodes :) 

Rishabh Joshi:
20150326 20:14:18
Sum of values of ALL THE LEADS, not just the deepest level. Cost me 2 WA. 
Added by:  Hector Navarro 
Date:  20130722 
Time limit:  1s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 
Resource:  Local UCV 2013. Walter Hernández 