/*
POJ 3264  Balanced Lineup
題目意思：給定Q（1<=Q<=200000)個數A1,A2,```,AQ,
多次求任一區間Ai-Aj中最大數和最小數的差 
*/
#include<stdio.h>
#include<algorithm>
#include<iostream>
using namespace std;
#define MAXN 200005
#define INF 10000000
int nMax,nMin;//記錄最大最小值 
struct Node
{
    int l,r;//區間的左右端點 
    int nMin,nMax;//區間的最小值和最大值 
}segTree[MAXN*3];
int a[MAXN];
void Build(int i,int l,int r)//在結點i上建立區間為(l,r)
{
    segTree[i].l=l;
    segTree[i].r=r;
    if(l==r)//葉子結點 
    {
        segTree[i].nMin=segTree[i].nMax=a[l];
        return;
    } 
    int mid=(l+r)>>1;
    Build(i<<1,l,mid);
    Build(i<<1|1,mid+1,r);
    segTree[i].nMin=min(segTree[i<<1].nMin,segTree[i<<1|1].nMin);
    segTree[i].nMax=max(segTree[i<<1].nMax,segTree[i<<1|1].nMax);   
}
void Query(int i,int l,int r)//查詢結點i上l-r的最大值和最小值
{
    if(segTree[i].nMax<=nMax&&segTree[i].nMin>=nMin)  return;
    if(segTree[i].l==l&&segTree[i].r==r)
    {
        nMax=max(segTree[i].nMax,nMax);
        nMin=min(segTree[i].nMin,nMin);
        return;
    }
    int mid=(segTree[i].l+segTree[i].r)>>1;
    if(r<=mid)   Query(i<<1,l,r);
    else if(l>mid)  Query(i<<1|1,l,r);
    else
    {
        Query(i<<1,l,mid);
        Query(i<<1|1,mid+1,r);
    }      
}
int main()
{
    int n,q;
    int l,r;
    int i;
    while(scanf("%d%d",&n,&q)!=EOF)
    {
        for(i=1;i<=n;i++)
          scanf("%d",&a[i]);
        Build(1,1,n);
        for(i=1;i<=q;i++)
        {
            scanf("%d%d",&l,&r);
            nMax=-INF;nMin=INF;
            Query(1,l,r);
            printf("%d\n",nMax-nMin);
        }    
    }  
    return 0;  
} 

#include <iostream>
#include <algorithm>
#include <numeric>
using namespace std;
#define MY_MIN  99999999
#define MY_MAX  -99999999


struct CNode
{
    int L,R;
    int nMin,nMax;
    CNode * pLeft, * pRight;
};
int nMax, nMin;
CNode Tree[1000000];
//CNode Tree[20];
int nCount = 0;
void BuildTree(CNode * pRoot, int L,int R)
{
    pRoot->L = L;
    pRoot->R = R;
    
    pRoot->nMin = MY_MIN;
    pRoot->nMax = MY_MAX;

    if ( L != R) {
        nCount ++;
        pRoot->pLeft = Tree + nCount;
        nCount ++;
        pRoot->pRight = Tree + nCount;
        BuildTree( pRoot->pLeft, L, ( L + R )/2);
        BuildTree( pRoot->pRight, (L + R) / 2 + 1,R);
    }
}
void Insert( CNode * pRoot , int i,int v)
{
    if( pRoot->L == i &&  pRoot->R == i ) {
        pRoot->nMin = pRoot->nMax = v;
        return;
    }
    pRoot->nMin = _cpp_min(pRoot->nMin,v);
    pRoot->nMax = _cpp_max(pRoot->nMax,v);
    if( i <= (pRoot->L + pRoot->R )/2 )
        Insert( pRoot->pLeft,i,v);
    else
        Insert( pRoot->pRight,i,v);
}
void Query(CNode * pRoot, int s, int e)
{
    if( pRoot->nMin >= nMin && pRoot->nMax <= nMax )
        return;
    if( s == pRoot->L && e == pRoot->R) {
        nMin = _cpp_min(pRoot->nMin,nMin);
        nMax = _cpp_max(pRoot->nMax,nMax);
        return ;
    }
    if( e <=  (pRoot->L + pRoot->R) / 2 )
        Query(pRoot->pLeft, s,e);
    else if( s >= (pRoot->L + pRoot->R) / 2 + 1)
        Query(pRoot->pRight, s,e);
    else {
        Query(pRoot->pLeft, s,(pRoot->L + pRoot->R) / 2);
        Query(pRoot->pRight, (pRoot->L + pRoot->R) / 2 + 1 ,e);
    }
}
int main()
{
    int n,q,h;
    int i,j,k;
    scanf("%d%d",&n,&q);
    nCount = 0;
    BuildTree(Tree,1,n);    
    for( i = 1;i <= n;i ++ ) {
        scanf("%d",&h);
        Insert( Tree,i,h);
    }
    for( i = 0;i < q;i ++ ) {
        int s,e;
        scanf("%d%d", &s,&e);
        nMax = MY_MAX;
        nMin = MY_MIN;
        Query(Tree,s,e);
        printf("%d\n",nMax - nMin);
    }
    return 0;
}