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  • Bzoj4869: [Shoi2017]相逢是问候

    题面

    传送门

    Sol

    摆定理

    [a^bequiv egin{cases} a^{b\%phi(p)}~~~~~~~~~~~gcd(a,p)=1\ a^b~~~~~~~~~~~~~~~~~~gcd(a,p) eq1,b<phi(p)\ a^{b\%phi(p)+phi(p)}~~~~gcd(a,p) eq1,bgeqphi(p) end{cases}~~~~~~~(mod~p) ]

    处理出(p)每次取(varphi)取到(1)为止的(varphi)值(注意还要取个1,可能存在其它的(p)(varphi)为1),最多(log)
    每次暴力修改,如果这个点被修改了超过了(p取varphi)的次数它就不会变了,那就不改了
    每个数只会最多改(log)次,所以复杂度对了
    直接搞luogu和loj上TLE了

    # include <bits/stdc++.h>
    # define RG register
    # define IL inline
    # define Fill(a, b) memset(a, b, sizeof(a))
    using namespace std;
    typedef long long ll;
    const int _(5e4 + 5), __(1e4 + 1);
    
    IL ll Read(){
        RG ll x = 0, z = 1; RG char c = getchar();
        for(; c < '0' || c > '9'; c = getchar()) z = c == '-' ? -1 : 1;
        for(; c >= '0' && c <= '9'; c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48);
        return x * z;
    }
    
    int n, m, c, prime[__], num, phi[30], lenp;
    bool isprime[__];
    
    IL void Sieve(){
    	isprime[1] = 1;
    	for(RG int i = 2; i < __; ++i){
    		if(!isprime[i]) prime[++num] = i;
    		for(RG int j = 1; j <= num && prime[j] * i < __; ++j){
    			isprime[i * prime[j]] = 1;
    			if(!(i % prime[j])) break;
    		}
    	}
    }
    
    IL int Phi(RG int x){
    	RG int cnt = x;
    	for(RG int i = 1; i <= num && prime[i] * prime[i] <= x; ++i){
    		if(x % prime[i]) continue;
    		while(!(x % prime[i])) x /= prime[i];
    		cnt -= cnt / prime[i];
    	}
    	if(x > 1) cnt -= cnt / x;
    	return cnt;
    }
    
    IL ll Pow(RG ll x, RG ll y, RG ll p){
    	RG int flg2 = 0, flg1 = 0; RG ll cnt = 1;
    	for(; y; y >>= 1){
    		if(y & 1) flg1 |= (cnt * x >= p || flg2), cnt = cnt * x % p;
    		flg2 |= (x * x >= p); x = x * x % p;
    	}
    	return cnt + flg1 * p;
    }
    
    IL ll Calc(RG int l, RG int r, RG ll x, RG ll p){
    	if(l == r) return Pow(x, 1, p);
    	return Pow(c, Calc(l + 1, r, x, phi[l + 1]), p);
    }
    
    int tim[_ << 2], sum[_ << 2], a[_];
    
    IL void Build(RG int x, RG int l, RG int r){
    	if(l == r){  sum[x] = a[l] = Read(); return;  }
    	RG int mid = (l + r) >> 1;
    	Build(x << 1, l, mid); Build(x << 1 | 1, mid + 1, r);
    	sum[x] = (sum[x << 1] + sum[x << 1 | 1]) % phi[0];
    }
    
    IL void Modify(RG int x, RG int l, RG int r, RG int L, RG int R){
    	if(tim[x] >= lenp) return;
    	if(l == r){  ++tim[x]; sum[x] = Calc(0, tim[x], a[l], phi[0]) % phi[0]; return;  }
    	RG int mid = (l + r) >> 1;
    	if(L <= mid) Modify(x << 1, l, mid, L, R);
    	if(R > mid) Modify(x << 1 | 1, mid + 1, r, L, R);
    	sum[x] = (sum[x << 1] + sum[x << 1 | 1]) % phi[0];
    	tim[x] = min(tim[x << 1], tim[x << 1 | 1]);
    }
    
    IL int Query(RG int x, RG int l, RG int r, RG int L, RG int R){
    	if(L <= l && R >= r) return sum[x];
    	RG int mid = (l + r) >> 1, ans = 0;
    	if(L <= mid) ans = Query(x << 1, l, mid, L, R);
    	if(R > mid) ans = (ans + Query(x << 1 | 1, mid + 1, r, L, R)) % phi[0];
    	return ans;
    }
    
    int main(RG int argc, RG char* argv[]){
    	Sieve(); n = Read(); m = Read(); RG int p = Read(); c = Read();
    	phi[0] = p;	while(p != 1) p = phi[++lenp] = Phi(p); phi[++lenp] = 1;
    	Build(1, 1, n);
    	for(RG int i = 1; i <= m; ++i){
    		RG int op = Read(), l = Read(), r = Read();
    		if(!op) Modify(1, 1, n, l, r);
    		else printf("%d
    ", Query(1, 1, n, l, r));
    	}
        return 0;
    }
    
    
    

    也可以直接强行去掉快速幂的(log)
    处理出两段(c的幂,记为pow),一段处理(10000)以内的,另一段处理以外的,查询时两端拼起来就好了

    int Query(int x,int a,int mm)
    {
        if (a <= 10000) return pow1[a][mm];
        return (1ll*pow2[a/10000][mm]*pow1[a%10000][mm])%phi[mm];
    }
    
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  • 原文地址:https://www.cnblogs.com/cjoieryl/p/8319117.html
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