acdream 20140730 D题

今天见识到了“数学上来先打表”............

#include<iostream>
using namespace std;
#include<iomanip>
#define LL long long
/*
int lowbit(int n)
{
    int t,cnt = 1;
    t = n % 2;
    if(t == 1) return 1;
    while(t == 0)
    {
        cnt *= 2;
        n /= 2;
        t = n % 2;
    }
    return cnt;
}
LL d(int n)
{
    LL ans = 0;
    for(int i = 1; i <= n; i++)
        ans += lowbit(i);
    return ans;
}
*/
//经过打表，得f(x) = 2 * f( x / 2) + n / 2 + ( n & 1 )
LL d(int n)
{
    if(n == 1)return 1;
    LL ans = 2 * d(n / 2) + n / 2 + (n & 1);
    return ans;
}
int main()
{
    int n;
    while(cin>>n)
    {
        cout<<d(n)<<endl;
    }
    return 0;
}

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