Recaman's Sequence

Time Limit: 3000MS		Memory Limit: 60000K
Total Submissions: 18575		Accepted: 7751

Description

The Recaman's sequence is defined by a0 = 0 ; for m > 0, a

_m = a

_m−1 − m if the rsulting a

_m is positive and not already in the sequence, otherwise a

_m = a

_m−1 + m.

The first few numbers in the Recaman's Sequence is 0, 1, 3, 6, 2, 7, 13, 20, 12, 21, 11, 22, 10, 23, 9 ...

Given k, your task is to calculate a

_k.

Input

The input consists of several test cases. Each line of the input contains an integer k where 0 <= k <= 500000.

The last line contains an integer −1, which should not be processed.

Output

For each k given in the input, print one line containing a

_k to the output.

Sample Input

710000-1

Sample Output

2018658

#include 
     
      #include 
      
       const int N=500010;int ch[N];bool vis[N*10];//状态数组一定要开得比数字数组大，否则测试时会ＲＥ void init(){    int i,j;    memset(vis,false,sizeof(vis));    memset(ch,0,sizeof(ch));    vis[0]=vis[1]=vis[3]=true;    ch[0]=0;ch[1]=1;    for(i=2;i