Codeforces1114F Please, another Queries on Array?

题目链接:http://codeforces.com/problemset/problem/1114/F

题意:序列$a$,有两种操作,1 区间里的数同时乘上$x$ 2 求区间的积的欧拉函数

线段树好题。

思路:最直观的思路是,线段树每个节点维护的是一个数组,表示这个数每个素因子及出现的次数,欧拉函数值用矩阵快速幂求解即可。但是这样空间不大够,而且复杂度多个常数,因此不大行。

发现300以内的素数刚好有62个,那么可以用一个long long的二进制数来表示这个数有那些素因子出现,在维护一下区间积,欧拉函数值可以用公式

$\varphi \left( n\right) =n\cdot \dfrac {\prod \left( p_{i}-1\right) }{\prod p_{i}}$

lazy_tag有两个,一个是异或,一个是乘积。我刚开始没用异或,准备直接用乘积来得到异或值,但是因为会取模,所以乘积标记不能用来得到位上的值。

#include <bits/stdc++.h>
#define lp p << 1
#define rp p << 1 | 1
#define ll long long
using namespace std;

template<typename T>
inline void read(T &x) {
    x = 0; T f = 1; char ch = getchar();
    while (ch < '0' || ch > '9') { if (ch == '-') f = -1; ch = getchar(); }
    while (ch >= '0' && ch <= '9') { x = x * 10 + ch - 48; ch = getchar() ;}
    x *= f;
}

const ll MOD = 1e9 + 7;
const int N = 4e5 + 10;
int prime[70], prin, a[N], n;
ll inv[300];
bool vis[300];

ll qp(ll a, ll b) {
    ll res = 1;
    while (b) {
        if (b & 1) res = res * a % MOD;
        a = a * a % MOD;
        b >>= 1;
    }
    return res;
}

inline ll getbin(ll x) {
    ll res = 0;
    for (int i = 0; i < prin; i++) 
        if (x % prime[i] == 0) res |= (1LL << i);
    return res;
}

struct SEG {
    ll appear[N << 4], num[N << 4], lazy[N << 4], lazy_bin[N << 4];
    void pushup(int p) {
        appear[p] |= (appear[lp] | appear[rp]);
        num[p] = num[lp] * num[rp] % MOD;
    }
    void pushdown(int p, int llen, int rlen) {    
        lazy[lp] = lazy[lp] * lazy[p] % MOD;
        lazy[rp] = lazy[rp] * lazy[p] % MOD;
        lazy_bin[lp] |= lazy_bin[p]; lazy_bin[rp] |= lazy_bin[p];
        appear[lp] |= lazy_bin[lp];
        appear[rp] |= lazy_bin[rp];
        num[lp] = num[lp] * qp(lazy[p], llen) % MOD;
        num[rp] = num[rp] * qp(lazy[p], rlen) % MOD;
        lazy[p] = 1;
        lazy_bin[p] = 0;
    }
    void build(int p, int l, int r) {
        appear[p] = num[p] = lazy_bin[p] = 0;
        lazy[p] = 1;
        if (l == r) {
            num[p] = a[l];
            appear[p] = getbin(a[l]);
            return;
        }
        int mid = l + r >> 1;
        build(lp, l, mid);
        build(rp, mid + 1, r);
        pushup(p);
    }
    void update(int p, int l, int r, int x, int y, ll v, ll bin) {
        if (x <= l && r <= y) {
            lazy_bin[p] |= bin;
            appear[p] |= bin;
            lazy[p] = lazy[p] * v % MOD;
            num[p] = num[p] * qp(v, r - l + 1) % MOD;
            return;
        }
        int mid = l + r >> 1;
        pushdown(p, mid - l + 1, r - mid);
        if (x <= mid) update(lp, l, mid, x, y, v, bin);
        if (y > mid) update(rp, mid + 1, r, x, y, v, bin);
        pushup(p);
    }
    void query(int p, int l, int r, int x, int y, ll &v, ll &bin) {
        if (x <= l && r <= y) {
            v = v * num[p] % MOD;
            bin |= appear[p];
            return;
        }
        int mid = l + r >> 1;
        pushdown(p, mid - l + 1, r - mid);
        if (x <= mid) query(lp, l, mid, x, y, v, bin);
        if (y > mid) query(rp, mid + 1, r, x, y, v, bin);
    }
} seg;

char s[20];

int main() {
    //freopen("in.txt", "r", stdin);
    for (int i = 2; i < 300; i++) {
        if (!vis[i]) prime[prin++] = i;
        for (int j = 0; j < prin && i * prime[j] < 300; j++) {
            vis[i * prime[j]] = 1;
            if (i % prime[j] == 0) break;
        }
    }
    inv[1] = 1;
    for (int i = 2; i < 300; i++) inv[i] = (MOD - MOD / i) * inv[MOD % i] % MOD;
    read(n);
    int q; read(q);
    for (int i = 1; i <= n; i++) read(a[i]);
    seg.build(1, 1, n);
    while (q--) {
        scanf("%s", s);
        if (s[0] == 'T') {
            int l, r;
            read(l); read(r);
            ll v = 1, bin = 0;
            seg.query(1, 1, n, l, r, v, bin);
            for (int i = 0; i < prin; i++) {
                if (bin >> i & 1) v = v * (prime[i] - 1) % MOD * inv[prime[i]] % MOD;
            }
            printf("%lld\n", v);
        } else {
            int l, r, w;
            read(l); read(r); read(w);
            seg.update(1, 1, n, l, r, w, getbin(w));
        }
    }
    return 0;
}
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转载自www.cnblogs.com/Mrzdtz220/p/11222830.html