Bzoj4869: [Shoi2017]相逢是問候
阿新 • • 發佈:2018-01-20
end build const space pow(x long long 一段 ont esp 個
每次暴力修改,如果這個點被修改了超過了\(p取\varphi\)的次數它就不會變了,那就不改了
每個數只會最多改\(log\)次,所以復雜度對了
直接搞luogu和loj上TLE了
題面
傳送門
Sol
擺定理
\[
a^b\equiv
\begin{cases}
a^{b\%\phi(p)}~~~~~~~~~~~gcd(a,p)=1\a^b~~~~~~~~~~~~~~~~~~gcd(a,p)\neq1,b<\phi(p)\a^{b\%\phi(p)+\phi(p)}~~~~gcd(a,p)\neq1,b\geq\phi(p)
\end{cases}~~~~~~~(mod~p)
\]
處理出\(p\)每次取\(\varphi\)取到\(1\)為止的\(\varphi\)值(註意還要取個1,可能存在其它的\(p\)的\(\varphi\)為1),最多\(log\)
每次暴力修改,如果這個點被修改了超過了\(p取\varphi\)的次數它就不會變了,那就不改了
每個數只會最多改\(log\)次,所以復雜度對了
直接搞
# 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\n", Query(1, 1, n, l, r)); } return 0; }
也可以直接強行去掉快速冪的\(log\)
處理出兩段\(c的冪,記為pow\),一段處理\(10000\)以內的,另一段處理以外的,查詢時兩端拼起來就好了
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];
}
Bzoj4869: [Shoi2017]相逢是問候