竞赛讨论区 > 求助:请问大佬们,C题为什么我这样会MLE啊(已解决)
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ruayy
编辑于 02-06 17:17
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求助:请问大佬们,C题为什么我这样会MLE啊(已解决)

//多测试数据
#include <iostream>
#include <algorithm>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
using namespace std;
using i64 = long long;
typedef pair<int, int> PII;

//模数
template<const int T>
struct ModInt {
    const static int mod = T;
    int x;
    ModInt(int x = 0) : x(x % mod) {}
    ModInt(long long x) : x(int(x % mod)) {} 
    int val() { return x; }
    ModInt operator + (const ModInt &a) const { int x0 = x + a.x; return ModInt(x0 < mod ? x0 : x0 - mod); }
    ModInt operator - (const ModInt &a) const { int x0 = x - a.x; return ModInt(x0 < 0 ? x0 + mod : x0); }
    ModInt operator * (const ModInt &a) const { return ModInt(1LL * x * a.x % mod); }
    ModInt operator / (const ModInt &a) const { return *this * a.inv(); }
    bool operator == (const ModInt &a) const { return x == a.x; };
    bool operator != (const ModInt &a) const { return x != a.x; };
    void operator += (const ModInt &a) { x += a.x; if (x >= mod) x -= mod; }
    void operator -= (const ModInt &a) { x -= a.x; if (x < 0) x += mod; }
    void operator *= (const ModInt &a) { x = 1LL * x * a.x % mod; }
    void operator /= (const ModInt &a) { *this = *this / a; }
    friend ModInt operator + (int y, const ModInt &a){ int x0 = y + a.x; return ModInt(x0 < mod ? x0 : x0 - mod); }
    friend ModInt operator - (int y, const ModInt &a){ int x0 = y - a.x; return ModInt(x0 < 0 ? x0 + mod : x0); }
    friend ModInt operator * (int y, const ModInt &a){ return ModInt(1LL * y * a.x % mod);}
    friend ModInt operator / (int y, const ModInt &a){ return ModInt(y) / a;}
    friend ostream &operator<<(ostream &os, const ModInt &a) { return os << a.x;}
    friend istream &operator>>(istream &is, ModInt &t){return is >> t.x;}

    ModInt pow(long long n) const {
        ModInt res(1), mul(x);
        while(n){
            if (n & 1) res *= mul;
            mul *= mul;
            n >>= 1;
        }
        return res;
    }
    ModInt inv() const {
        int a = x, b = mod, u = 1, v = 0;
        while (b) {
            int t = a / b;
            a -= t * b; swap(a, b);
            u -= t * v; swap(u, v);
        }
        if (u < 0) u += mod;
        return u;
    }
};
using mint = ModInt<1000000007>;

//01字典树
struct Trie{
	vector<vector<int>> trie;
	vector<int> tag;
	const int mod = 1e9 + 7;
	int cnt;
	Trie(){}
	//n为整数数目,31为int范围
	Trie(int n){
		cnt = 0;
		trie.assign(n * 31, vector<int>(2));
		tag.assign(n * 31, 0);
	}
	void insert(int x, int v){
		int idx = 0;
		for(int i = 30; i >= 0; i--){
			if(!trie[idx][(x >> i) & 1]){
				trie[idx][(x >> i) & 1] = ++cnt;
			}
			idx = trie[idx][(x >> i) & 1];
			tag[idx] = (tag[idx] + v) % mod;
		}
	}
	i64 query(int x, int k){
		i64 ret = 0;
		int idx = 0;
		for(int i = 30; i >= 0; i--){
			int e = (x >> i) & 1;
			if((k >> i) & 1){
				ret = (ret + tag[trie[idx][e]]) % mod;
				idx = trie[idx][1 - e];
			}
			else {
				idx = trie[idx][e];
			}
			if(!idx) return ret;
		}
		return (ret + tag[idx]) % mod;
	}
};

const int MAXN = 2e5 + 5;
vector<mint> pow2(MAXN), invpow2(MAXN);

inline void init(){
	pow2[0] = 1;
	for(int i = 1; i < MAXN; i++){
		pow2[i] = pow2[i - 1] * 2;
	}
	invpow2[MAXN - 1] = pow2[MAXN - 1].inv();
	for(int i = MAXN - 2; i >= 0; i--){
		invpow2[i] = invpow2[i + 1] * 2;
	}
}

void solve(){
	int n, k;
	cin >> n >> k;
	vector<int> a(n + 1);
	for(int i = 1; i <= n; i++){
		cin >> a[i];
	}
	sort(a.begin() + 1, a.end());
	Trie trie(n + 1);
	mint res = n;
	for(int i = 1; i <= n; i++){
		res += pow2[i - 1].val() * trie.query(a[i], k);
		trie.insert(a[i], invpow2[i].val());
	}
	cout << res << '\n';
}

signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);
	init();
	int T = 1; cin >> T;
	while(T--) solve();
	return 0;
}

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