HDU 4349 Xiao Ming's Hope ( Lucas

　题意：

求　$n$个组合数的奇数有几个
组合数的一个性质　$(n&m)==n$的话　这个数就是奇数，　这个性质在这个题里面不可写
我们需要利用Lucas 定理　发现规律　就是统计里面一共有几个数即可

#include <bits/stdc++.h>

using namespace std;

#define ll long long 
#define pb push_back
#define ls o<<1
#define rs o<<1|1
#define fi first
#define se second
#define CLR(a, b) memset(a, (b), sizeof(a))
const int INF = 0x3f3f3f3f;
const int mod = 1e9+7;
const int MAXN = 1e4+10;

void F() {
    #ifndef ONLINE_JUDGE
        freopen("in.txt", "r", stdin);
    #endif
}

ll pow_mod(ll a, ll b, ll p) {
    ll res = 1;
    while(b) {
        if(b&1) res = res*a%p;
        a = a*a%p;
        b >>= 1;
    }
    return res;
}
ll inv(ll x, ll p) {
    return pow_mod(x, p-2, p)%p;
}
ll C(ll a, ll b, ll p) {
    if(a < b) return 0LL;
    ll ans = 1;
    for(int i = 1; i <= b; ++i ) {
        ans = ans*(((a+i-b)%p)*inv(i, p)%p)%p;
    }
    return ans;
}
ll lucas(ll a, ll b, ll p) {
    if(b == 0) return 1;
    return C(a%p, b%p, p)*lucas(a/p, b/p, p)%p;
}


int main() {
    F();
    ll n;
    while(cin >> n) {
        int k = 0;
        while(n) {
            if(n&1) k++;
            n >>= 1;
        }
        cout << (1<<k) << endl;
    }
    return 0;
}