HDU 5014 贪心

#include "stdio.h"
#include "string.h"
int main()
{
int n,i,j,sum;
__int64 ans;
int b[100010],a[100010];
while (scanf("%d",&n)!=EOF)
{
for (i=0;i<=n;i++)
scanf("%d",&a[i]);
memset(b,-1,sizeof(b));

ans=0;
for (i=n;i>=0;i--)
if (b[i]==-1)
{
sum=0;
for (j=1;sum<i;j*=2)
{
if (sum+j>=i) break;
if ((j&i)==0) sum+=j;

}

ans+=(sum^i)+(sum^i);
b[i]=sum;
b[sum]=i;
}
printf("%I64d\n",ans);a
for (i=0;i<n;i++)
printf("%d ",b[a[i]]);
printf("%d\n",b[a
]);
}
return 0;
}