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  • CF959E Mahmoud and Ehab and the xor-MST 思维

    Ehab is interested in the bitwise-xor operation and the special graphs. Mahmoud gave him a problem that combines both. He has a complete graph consisting of n vertices numbered from 0 to n - 1. For all 0 ≤ u < v < n, vertex u and vertex v are connected with an undirected edge that has weight (where is the bitwise-xor operation). Can you find the weight of the minimum spanning tree of that graph?

    You can read about complete graphs in https://en.wikipedia.org/wiki/Complete_graph

    You can read about the minimum spanning tree in https://en.wikipedia.org/wiki/Minimum_spanning_tree

    The weight of the minimum spanning tree is the sum of the weights on the edges included in it.

    Input

    The only line contains an integer n (2 ≤ n ≤ 1012), the number of vertices in the graph.

    Output

    The only line contains an integer x, the weight of the graph's minimum spanning tree.

    Example
    Input
    Copy
    4
    Output
    Copy
    4
    Note

    In the first sample: The weight of the minimum spanning tree is 1+2+1=4.

    题意翻译

    n个点的完全图标号(0-n-1),i和j连边权值为i^j,求MST的值

    不妨先手算几项,可以发现每一位上的贡献为当前n 的一半;

    #include<iostream>
    #include<cstdio>
    #include<algorithm>
    #include<cstdlib>
    #include<cstring>
    #include<string>
    #include<cmath>
    #include<map>
    #include<set>
    #include<vector>
    #include<queue>
    #include<bitset>
    #include<ctime>
    #include<deque>
    #include<stack>
    #include<functional>
    #include<sstream>
    //#include<cctype>
    //#pragma GCC optimize("O3")
    using namespace std;
    #define maxn 300005
    #define inf 0x3f3f3f3f
    #define INF 9999999999
    #define rdint(x) scanf("%d",&x)
    #define rdllt(x) scanf("%lld",&x)
    #define rdult(x) scanf("%lu",&x)
    #define rdlf(x) scanf("%lf",&x)
    #define rdstr(x) scanf("%s",x)
    typedef long long  ll;
    typedef unsigned long long ull;
    typedef unsigned int U;
    #define ms(x) memset((x),0,sizeof(x))
    const long long int mod = 1e9 + 7;
    #define Mod 1000000000
    #define sq(x) (x)*(x)
    #define eps 1e-3
    typedef pair<int, int> pii;
    #define pi acos(-1.0)
    //const int N = 1005;
    #define REP(i,n) for(int i=0;i<(n);i++)
    
    inline ll rd() {
    	ll x = 0;
    	char c = getchar();
    	bool f = false;
    	while (!isdigit(c)) {
    		if (c == '-') f = true;
    		c = getchar();
    	}
    	while (isdigit(c)) {
    		x = (x << 1) + (x << 3) + (c ^ 48);
    		c = getchar();
    	}
    	return f ? -x : x;
    }
    
    ll gcd(ll a, ll b) {
    	return b == 0 ? a : gcd(b, a%b);
    }
    ll sqr(ll x) { return x * x; }
    
    /*ll ans;
    ll exgcd(ll a, ll b, ll &x, ll &y) {
    	if (!b) {
    		x = 1; y = 0; return a;
    	}
    	ans = exgcd(b, a%b, x, y);
    	ll t = x; x = y; y = t - a / b * y;
    	return ans;
    }
    */
    
    
    
    ll qpow(ll a, ll b, ll c) {
    	ll ans = 1;
    	a = a % c;
    	while (b) {
    		if (b % 2)ans = ans * a%c;
    		b /= 2; a = a * a%c;
    	}
    	return ans;
    }
    
    
    
    int main()
    {
    	//ios::sync_with_stdio(0);
    	ll n; rdllt(n);
    	ll ans = 0;
    	ll tmp = 1;
    	while (n>1) {
    		ans += tmp * (n >> 1); tmp <<= 1; n -= (n >> 1);
    	//	cout << n<<' '<<ans << endl;
    	}
    	cout << ans << endl;
        return 0;
    }
    
    EPFL - Fighting
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  • 原文地址:https://www.cnblogs.com/zxyqzy/p/10017081.html
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