hdu 5524 二叉树找规律，二进制相关

input

n 1<=n<=1e18

output

有n个结点的满二叉树有多少个不相同结点数的子树

做法：树有h=log2(n)层，最多有2h-2种(1除外),然后再n减去u重复的即可

#include <bits/stdc++.h>
#include <cstdio>
#include <queue>
#include <cstring>
#include <iostream>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <map>
#include <set>
#include <ctime>
#include <cmath>
#include <cctype>
#include <string>
#include <bitset>
#define MAX 100000
#define LL long long
using namespace std;
LL n;
int highbit(LL x)
{
    for(int i=63;i>=0;i--) if(x&(1LL<<i)) return i+1;
}
int lowbit(LL x)
{
    for(int i=0;i<=63;i++) if(x&(1LL<<i)) return i;
}
int main()
{
    freopen("in","r",stdin);
    //scanf("%d",&T);
    while(scanf("%lld",&n)==1)
    {
        int h=highbit(n);
        LL maxn=(1LL<<h)-1;LL mid=maxn-(1LL<<(h-2>=0?h-2:0));
//        printf("%lld:",n);
//        printf("h=%d maxn=%lld mid=%lld
",h,maxn,mid);
        if(n==maxn||n==mid) { printf("%d
",h);continue; }
        h+=h-2;
        if(n<=mid) h--;
        h-=lowbit(n-(maxn>>1));
        printf("%d
",h);
    }
    //printf("time=%.3lf",(double)clock()/CLOCKS_PER_SEC);
    return 0;
}