洛谷P3865

#include <bits/stdc++.h>
/*
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/hash_policy.hpp>
*/
using namespace std;

const double eps = 1e-10;
const double pi = 3.1415926535897932384626433832795;
const double eln = 2.718281828459045235360287471352;

#define f(i, a, b) for (int i = a; i <= b; i++)
#define scan(x) scanf("%d", &x)
#define mp make_pair
#define pb push_back
#define lowbit(x) (x&(-x))

#define fi first
#define se second
#define SZ(x) int((x).size())
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define summ(a) (accumulate(all(a), 0ll))

typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;

using ll=long long;

ll n,m,a[(int)1e5+9],f[(int)1e5+9][21],lo[(int)1e5+9];

inline ll rmq(int l,int r){
    int k=lo[r-l+1];
    return max(f[l][k],f[r-(1ll<<k)+1][k]);
}

int main()
{
    scanf("%lld%lld",&n,&m);
    for(int i=1;i<=n;++i)scanf("%lld",&a[i]);
    for(int i=1;i<=n;++i)f[i][0]=a[i];
    for(int i=2;i<=n;++i)lo[i]=lo[i>>1]+1;
    for(int j=1;j<=20;++j){
        for(int i=1;i+(1ll<<j)-1<=n;++i){
            f[i][j]=max(f[i][j-1],f[i+(1ll<<(j-1))][j-1]);
        }
    }
    for(int i=1,x,y;i<=m;++i){
        scanf("%d%d",&x,&y);
        printf("%lld\n",rmq(x,y));
    }
    return 0;
}