Coderforces-906D Power tower

欧拉降幂定理：

这道题写euler中错了，在第32组样例上TLE了无数次，崩了~

ac代码：

#include<cstdio>
#include<iostream>
#include<cmath>
#include<map>
#define ll long long
using namespace std;

const int maxn = 100010;
map<ll, ll> aria;
ll w[maxn];

ll mods(ll n, ll mod)
{
    if(n < mod){
        return n;
    }
    else	return n%mod+mod;
}

ll powmod(ll a, ll b, ll mod)
{
    ll ret = 1;
    while(b){
        if(b & 1){
            ret = mods(ret*a, mod);
        }
        a = mods(a*a, mod);
        b >>= 1;
    }
    return ret;
}

ll euler(ll x)
{
    ll res = x, ans = res;
    if(aria[x]!= 0)	return aria[x];
    for(ll i = 2; i < (ll)sqrt(x*1.0)+1; i++){
        if(x % i == 0){
            res = res / i * (i-1);
            while(x % i == 0)	x /= i;
        }
    }
    if(x > 1)	res = res / x * (x-1);
    aria[ans] = res;
    return res;
}

ll solve(ll l, ll r, ll mod)
{
    if(l == r || mod == 1)	return mods(w[l], mod);
    return powmod(w[l], solve(l+1, r, euler(mod)), mod);
}

int main()
{
	int n, m, q;
    scanf("%d %d", &n, &m);
    for(int i = 1; i <= n; i++){
        scanf("%lld", &w[i]);
    }
    scanf("%d", &q);
    for(int i = 1; i <= q; i++){
        int l, r;
        scanf("%d %d", &l, &r);
        printf("%lld\n", solve(l, r, m)%m);
    }
    return 0;
}

自己的题目做的还是太少，诶~。。。