#include<bits/stdc++.h>
using namespace std;
#define ll long long
struct node
{
	int l,r;
	int maxn,minn;
}tree[400010];
void build(int i,int l,int r)
{
 	tree[i].l=l;tree[i].r=r;tree[i].maxn=0;tree[i].minn=0x3f3f3f3f;
 	if(l==r)
 	{
 		cin>>tree[i].minn;
 		tree[i].maxn=tree[i].minn;
 		return ;
 	}
 	int mid=(l+r)/2;
 	build(i*2,l,mid);
 	build(i*2+1,mid+1,r);
 	tree[i].maxn=max(tree[i*2].maxn,tree[i*2+1].maxn);
 	tree[i].minn=min(tree[i*2].minn,tree[i*2+1].minn);
}
void search(int i,int l,int r,int &minn,int &maxn)
{
 	if(tree[i].l>=l&&tree[i].r<=r)
 	{
 	 	minn=min(minn,tree[i].minn);
	 	maxn=max(maxn,tree[i].maxn);
	 	return ;	
	}
	if(tree[i*2].r>=l) search(i*2,l,r,minn,maxn);
	if(tree[i*2+1].l<=r) search(i*2+1,l,r,minn,maxn);
}
int main()
{
	ios::sync_with_stdio(false);
    int n,m,a,b,maxn,minn;
    while(cin>>n>>m)
    {
     	build(1,1,n);
     	while(m--)
     	{
      		cin>>a>>b;
      		maxn=0,minn=0x3f3f3f3f;
      		search(1,a,b,minn,maxn);
      		cout<<maxn-minn<<endl;
	 	}    	
	}
    return 0;
}