1 /* ***********************************************
 2 MYID    : Chen Fan
 3 LANG    : G++
 4 PROG    : HDU5172
 5 ************************************************ */
 6 
 7 #include <iostream>
 8 #include <cstdio>
 9 #include <cstring>
10 #include <algorithm>
11 
12 using namespace std;
13 
14 const int N=1e6+10;
15 
16 int last[N],a,sum[N];
17  
18 typedef struct treetyp
19 {
20     int a,b,l,r,data;
21 } treetype;
22 treetype tree[2*N];
23 int treetail;
24 
25 void maketree(int l,int r)
26 {
27     treetail++;
28     int now=treetail;
29     tree[now].a=l;
30     tree[now].b=r;
31     if (l<r)
32     {
33         tree[now].l=treetail+1;
34         maketree(l,(l+r)/2);
35         tree[now].r=treetail+1;
36         maketree((l+r)/2+1,r);
37     }
38 }
39 
40 void add(int n,int i,int data)
41 {
42     if (tree[n].data<data) tree[n].data=data;
43     if (i==tree[n].a&&i==tree[n].b) return ;
44     else if (i<=(tree[n].a+tree[n].b)/2) add(tree[n].l,i,data);
45          else add(tree[n].r,i,data);
46 }
47 
48 int res;
49 
50 void search(int n,int a,int b)
51 {
52     if (tree[n].a>=a&&tree[n].b<=b)
53     {
54         if (res<tree[n].data) res=tree[n].data;
55         return ;
56     }
57     if (tree[n].a==tree[n].b) return ;
58     if (a<=(tree[n].a+tree[n].b)/2) search(tree[n].l,a,b);
59     if (b>=(tree[n].a+tree[n].b)/2+1) search(tree[n].r,a,b);
60 }
61 
62 int main()
63 {
64     int n,m;
65     while(scanf("%d%d",&n,&m)==2)
66     {
67         memset(sum,0,sizeof(sum));
68         memset(last,0,sizeof(last));
69 
70         treetail=0;
71         maketree(1,n);
72         for (int i=1;i<=n;i++) 
73         {
74             scanf("%d",&a);
75             sum[i]=sum[i-1]+a;
76             add(1,i,last[a]);
77             last[a]=i;
78         }
79 
80         for (int i=1;i<=m;i++)
81         {
82             int l,r;
83             scanf("%d%d",&l,&r);
84             if ((r-l+1)*(r-l+2)/2==sum[r]-sum[l-1])
85             {
86                 res=0;
87                 search(1,l,r);
88                 if (res<l) printf("YES\n");
89                 else printf("NO\n");
90             } else printf("NO\n");
91         }
92     }
93 
94     return 0;
95 }