#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <string.h>
#include <math.h>
#define ll long long
using namespace std;
const int maxn=5e4+10;
int maxnum[maxn][20];
int minnum[maxn][20];
void RMQ(int num)
{
    for(int j=1;j<20;j++)
    {
        for(int i=1;i<=num;i++)
        {
            if(i+(1<<j)-1<=num)
            {
            maxnum[i][j]=max(maxnum[i][j-1],maxnum[i+(1<<(j-1))][j-1]);
            minnum[i][j]=min(minnum[i][j-1],minnum[i+(1<<(j-1))][j-1]);
            }
        }
    }
}
int n,m,st,en;
int main()
{
    while(~scanf("%d%d",&n,&m))
    {
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&maxnum[i][0]);
            minnum[i][0]=maxnum[i][0];
        }
        RMQ(n);
        while(m--)
        {
            scanf("%d%d",&st,&en);
            int k=(int)((log(en-st+1))/log(2.0));
            int max1,min1;
            max1=max(maxnum[st][k],maxnum[en-(1<<k)+1][k]);
            min1=min(minnum[st][k],minnum[en-(1<<k)+1][k]);
            printf("%d\n",max1-min1);
        }
    }
}