HDU 5014 Number Sequence（位运算）

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 using namespace std;
 6 typedef __int64 LL;
 7 const int maxn = 100005;
 8 int a[maxn],ans[maxn],visit[maxn];
 9 int get(int d)
10 {
11     int num = 0;
12     while(d)
13     {
14         d >>= 1;
15         num++;
16     }
17     return num;
18 }
19 
20 int main()
21 {
22     int n;
23     while(scanf("%d",&n)!=EOF)
24     {
25         for(int i = 0;i <= n;++i)
26         scanf("%d",&a[i]);
27         memset(visit,0,sizeof(visit));
28         memset(ans,0,sizeof(ans));
29         for(int i = n;i > 0;--i)
30         {
31             if(visit[i]) continue;
32             int d = get(i);
33             int temp = ((1 << d) - 1)  ^ i;
34             ans[i] = temp;
35             ans[temp] = i;
36             visit[temp] = visit[i] = 1;
37         }
38         LL sum = 0;
39         for(int i = 0;i <= n;++i)
40         sum += (LL)(i ^ ans[i]);
41         printf("%I64d\n",sum);
42         for(int i = 0;i <= n;++i)
43         printf(i == n? "%d\n":"%d ",ans[a[i]]);
44     }
45     return 0;
46 }