1 #include<cstdio> 2 #include<cstdlib> 3 #include<cmath> 4 #include<cstring> 5 #include<algorithm> 6 #include<iostream> 7 #include<vector> 8 #include<map> 9 #include<set>10 #include<queue>11 #include<string>12 #define inf 100000000013 #define maxn 250000+514 #define maxm 500+10015 #define eps 1e-1016 #define ll long long17 #define pa pair<int,int>18 #define for0(i,n) for(int i=0;i<=(n);i++)19 #define for1(i,n) for(int i=1;i<=(n);i++)20 #define for2(i,x,y) for(int i=(x);i<=(y);i++)21 #define for3(i,x,y) for(int i=(x);i>=(y);i--)22 #define mod 100000000723 using namespace std;24 inline int read()25 {26     int x=0,f=1;char ch=getchar();27     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}28     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}29     return x*f;30 }31 int n,m,a[maxn],v[maxn],sg[maxn],next[maxn],ans[maxn];32 struct seg{int l,r,mi;}t[4*maxn];33 struct rec{int l,r,id;}c[maxn];34 inline void build(int k,int l,int r)35 {36     t[k].l=l;t[k].r=r;int mid=(l+r)>>1;37     t[k].mi=inf;38     if(l==r){t[k].mi=sg[l];return;}39     build(k<<1,l,mid);build(k<<1|1,mid+1,r);40 }41 inline void update(int k,int z)42 {43     t[k].mi=min(t[k].mi,z);44 }45 inline void pushdown(int k)46 {47     if(t[k].mi==inf)return;48     update(k<<1,t[k].mi);49     update(k<<1|1,t[k].mi);50     t[k].mi=inf;51 }52 inline void change(int k,int x,int y,int z)53 {54     int l=t[k].l,r=t[k].r,mid=(l+r)>>1;55     if(l==x&&r==y){update(k,z);return;}56     pushdown(k);57     if(y<=mid)change(k<<1,x,y,z);58     else if(x>mid)change(k<<1|1,x,y,z);59     else change(k<<1,x,mid,z),change(k<<1|1,mid+1,y,z);60 }61 inline int query(int k,int x)62 {63     int l=t[k].l,r=t[k].r,mid=(l+r)>>1;64     if(l==r)return t[k].mi;65     pushdown(k);66     if(x<=mid)return query(k<<1,x);else return query(k<<1|1,x);67 }68 inline bool cmp(rec x,rec y){return x.l<y.l;}69 int main()70 {71     freopen("input.txt","r",stdin);72     freopen("output.txt","w",stdout);73     n=read();m=read();int k=0;74     for1(i,n)75     {76         a[i]=read();77         v[a[i]]=1;78         if(a[i]==k){while(v[k])k++;}79         sg[i]=k;80     }81     memset(v,0,sizeof(v));82     build(1,1,n);83     for1(i,m)c[i].l=read(),c[i].r=read(),c[i].id=i;84     sort(c+1,c+m+1,cmp);85     for3(i,n,1)next[i]=v[a[i]],v[a[i]]=i;86     int now=1;87     for1(i,m)88     {89         while(now<c[i].l)90         {91             if(!next[now])next[now]=n+1;92             if(next[now]-1>=now+1)change(1,now+1,next[now]-1,a[now]);93             now++;94         }95         ans[c[i].id]=query(1,c[i].r);96     }97     for1(i,m)printf("%d\n",ans[i]);98     return 0;99 }