P3709 uncle string title (Mo Team)

Portal

First, this question surfaces curved around school do not understand

Glanced at the solution to a problem is to find the number of occurrences of the mode inside a range.

Because this interval does not change, offline, then the team on the line Mo

Mo team seeking the mode, write x number of occurrences cnt [x], record the number of occurrences is the number n is the number of num [n], the number of times the current number is now public

Add then directly modify cnt and num, with cnt to update now

Deleted, if the time num [cnt [x]] == 1 and cnt [x] == now, then later delete x, there is no cnt == now the number, now--. You can not be handled like code

#include <iostream>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <algorithm>
#define MAXN 200010
using namespace std;
int n,m,a[MAXN],b[MAXN],pos[MAXN],ans[MAXN],cnt[MAXN],num[MAXN],now;

struct Ques{
    int l,r,id;
}q[MAXN];

bool cmp(Ques x,Ques y){return pos[x.l]<pos[y.l]||pos[x.l]==pos[y.l]&&x.r<y.r;}

void add(int x){
    num[cnt[x]]--;
    num[++cnt[x]]++;
    now=max(now,cnt[x]);
}

void del(int x){
    num[cnt[x]]--;
    if(cnt[x]==now&&!num[cnt[x]]) now--;
    num[--cnt[x]]++;
}

int main(){
    scanf("%d%d",&n,&m);
    int sz=sqrt(n);
    for(int i=1;i<=n;i++) scanf("%d",&a[i]),b[i]=a[i],pos[i]=i/sz;
    sort(b+1,b+n+1);
    int tot=unique(b+1,b+n+1)-b-1;
    for(int i=1;i<=n;i++) a[i]=lower_bound(b+1,b+tot+1,a[i])-b;
    for(int i=1;i<=m;i++) scanf("%d%d",&q[i].l,&q[i].r),q[i].id=i;
    sort(q+1,q+m+1,cmp);
    int L=0,R=0;
    num[0]=tot;
    for(int i=1;i<=m;i++){
        while(R<q[i].r) add(a[++R]);
        while(R>q[i].r) del(a[R--]);
        while(L>q[i].l) add(a[--L]);
        while(L<q[i].l) del(a[L++]);
        ans[q[i].id]=-now;
    }
    for(int i=1;i<=m;i++) printf("%d\n",ans[i]);
    return 0;
}