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Number Sequence

4
2 0 1 4 3

20
1 0 2 3 4

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>

using namespace std;

int n,a[100100],sig[100100];
long long int ans;

int wei(int x)
{
    if(x==0) return 0;
    return log(x*1.)/log(2.0);
}

int main()
{
    while(scanf("%d",&n)!=EOF)
    {
        ans=0;
        memset(sig,-1,sizeof(sig));
        for(int i=n;i>=0;i--) 
        {
            if(n%2==0&&i==0) 
            {
                sig[0]=0;
                continue;
            }
            if(sig[i]!=-1)
            {
                ans+=i^sig[i];
                continue;
            }
            int w=wei(i);    
            w++;
            int fan=((1<<w)-1)^i;
            sig[i]=fan;
            sig[fan]=i;
            ans+=i^sig[i];
        }
        printf("%I64d\n",ans);
        for(int i=0;i<=n;i++)
        {
            int x;
            scanf("%d",&x);
            if(i) putchar(32);
            printf("%d",sig[x]);
        }
        putchar(10);
    }
    return 0;
}

HDOJ 5014 Number Sequence

原文：http://blog.csdn.net/ck_boss/article/details/39276653