思路：
按权值建一棵主席树
（但是这好像不是正解 空间复杂度是不对的…….）
//By SiriusRen
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
#define N 555555
int n,m,cnt,root[N],a[N],xx,yy;
struct Tree{int l,r,num;}tree[N*20];
void push_up(int pos){tree[pos].num=tree[tree[pos].l].num+tree[tree[pos].r].num;}
int build(int l,int r){
int pos=++cnt;
if(l==r){return pos;}
int mid=(l+r)>>1;
tree[pos].l=build(l,mid),tree[pos].r=build(mid+1,r);
return pos;
}
int insert(int o,int l,int r,int num){
int pos=++cnt;tree[pos]=tree[o];
if(l==r){tree[pos].num++;return pos;}
int mid=(l+r)>>1;
if(num<=mid)tree[pos].l=insert(tree[o].l,l,mid,num);
else tree[pos].r=insert(tree[o].r,mid+1,r,num);
push_up(pos);
return pos;
}
int query(int o,int v,int l,int r,int wei){
if(tree[o].num-tree[v].num<=wei)return 0;
if(l==r)return l;
int mid=(l+r)>>1;
if(tree[tree[o].l].num-tree[tree[v].l].num>wei)
return query(tree[o].l,tree[v].l,l,mid,wei);
else return query(tree[o].r,tree[v].r,mid+1,r,wei);
}
int main(){
scanf("%d%d",&n,&m);
root[0]=build(1,n);
for(int i=1;i<=n;i++)scanf("%d",&a[i]),root[i]=insert(root[i-1],1,n,a[i]);
for(int i=1;i<=m;i++){
scanf("%d%d",&xx,&yy);
printf("%d
",query(root[yy],root[xx-1],1,n,(yy-xx+1)/2));
}
}