1 #include <bits/stdc++.h>
 2 
 3 using namespace std;
 4 
 5 const int MAXN = 50000;
 6 
 7 typedef struct
 8 {
 9     int left,right,maxv,minv;
10 }Node;
11 Node rt[MAXN<<2];
12 int a[MAXN+5];
13 
14 void build(int x, int L, int R)
15 {
16     rt[x].left = L; rt[x].right = R;
17     if(L==R)
18     {
19         rt[x].maxv = rt[x].minv = a[L];
20         return ;
21     }
22     int mid = L + R >>1;
23     build(x<<1,L,mid); build((x<<1)+1,mid+1,R);
24     rt[x].maxv = max(rt[x<<1].maxv,rt[(x<<1)+1].maxv);
25     rt[x].minv = min(rt[x<<1].minv,rt[(x<<1)+1].minv);
26 }
27 
28 Node query(int x, int L, int R)
29 {
30     Node t,tt;
31     int mid = (rt[x].left + rt[x].right)>>1;
32     if(L == rt[x].left && R == rt[x].right)
33     {
34         return rt[x];
35     }
36     else if(R<=mid)
37     {
38         tt = query(x<<1,L,R);
39         t.maxv = tt.maxv;
40         t.minv = tt.minv;
41         return t;
42     }
43     else if(L>mid)
44     {
45         tt = query((x<<1)+1,L,R);
46         t.maxv = tt.maxv;
47         t.minv = tt.minv;
48         return t;
49     }
50     else
51     {
52         t = query(x<<1,L,mid);
53         tt = query((x<<1)+1,mid+1,R);
54         t.maxv = max(t.maxv,tt.maxv);
55         t.minv = min(t.minv,tt.minv);
56         return t;
57     }
58 
59 }
60 
61 int main()
62 {
63     int n,q,l,r;
64     Node t;
65     scanf("%d %d",&n,&q);
66     for(int i=1;i<=n;++i)
67         scanf("%d",&a[i]);
68     build(1,1,n);
69     //for(int i=1;i<=9;++i)
70         //printf("%d,%d\t",rt[i].maxv,rt[i].minv);
71     while(q--)
72     {
73         scanf("%d %d",&l,&r);
74         t = query(1,l,r);
75         printf("%d\n",t.maxv-t.minv);
76     }
77 
78     return 0;
79 }