题意
题解
1 #include<iostream>
2 #include<cstring>
3 #include<cstdio>
4 #include<cmath>
5 #include<algorithm>
6 using namespace std;
7 const int N=100100;
8 int n,m,Block,block[N],a[N],b[N],cnt[400][N],top,stack[N],num[N];
9 long long f[400][N];
10 int main(){
11 scanf("%d%d",&n,&m);
12 Block=sqrt(n);
13 for(int i=1;i<=n;i++){
14 scanf("%d",&a[i]);
15 block[i]=(i-1)/Block+1;
16 b[i]=a[i];
17 }
18 sort(b+1,b+1+n);
19 int tot=unique(b+1,b+1+n)-b-1;
20 for(int i=1;i<=n;i++){
21 a[i]=lower_bound(b+1,b+1+tot,a[i])-b;
22 }
23 for(int i=1;i<=block[n];i++){
24 long long ans=0;
25 for(int j=lower_bound(block+1,block+1+n,i)-block;j<=n;j++){
26 cnt[i][a[j]]++;
27 ans=max(ans,(long long)cnt[i][a[j]]*b[a[j]]);
28 f[i][j]=ans;
29 }
30 }
31 for(int i=1;i<=m;i++){
32 top=0;
33 int x,y;
34 scanf("%d%d",&x,&y);
35 long long ans=f[block[x]+1][y];
36 int tmp=lower_bound(block+1,block+1+n,block[y])-block;
37 for(int j=tmp;j<=y;j++){
38 num[a[j]]++;
39 stack[++top]=a[j];
40 }
41 tmp=lower_bound(block+1,block+1+n,block[x]+1)-block;
42 for(int j=x;j<=tmp-1;j++){
43 num[a[j]]++;
44 ans=max(ans,(long long)(cnt[block[x]+1][a[j]]-cnt[block[y]][a[j]]+num[a[j]])*b[a[j]]);
45 stack[++top]=a[j];
46 }
47 printf("%lld\n",ans);
48 for(int j=1;j<=top;j++)num[stack[j]]=0;
49 }
50 return 0;
51 }
