# Acdream 1427 nice sequence

Source: Internet
Author: User
Tags integer numbers

Nice sequencetime limit: 12000/6000 ms (Java/others) memory limit: 128000/64000 KB (Java/others) submitstatisticnext problemproblem description

Let us consider the sequence A1, A2 ,..., an of non-negative integer numbers. denote as ci, j the number of occurrences of the number I among A1, A2 ,..., AJ. we call the sequence K-nice if for all I1 <I2 and for all j the following condition is satisfied: CI1, J ≥ci2, J? K.

Given the sequence A1, A2,..., an and the number k, find its longest prefix that is k-nice.

Input the first line of the input file contains N and K (1 ≤ n ≤ 200 000, 0 ≤ k ≤ 200 000 ). the second line contains N integer numbers ranging from 0 to n. output output the greatest LSuch that the sequence A1, A2,..., Al is k-nice.Sample Input
`10 10 1 1 0 2 2 1 2 2 32 01 0`
Sample output
`80`
Sourceandrew stankevich contest 23 managermathlover

Question and code:

This question was written by teammates during the competition. Because optimization was required during the query, a line segment tree was added to him to maintain the minimum value of the interval.

I read this question today, and it is not difficult. The definition of it is a bit difficult, in fact, when we input an element x from left to right, to ensure that its left element 1-(x-1) if the number of occurrences is greater than or equal to X, locate the longest prefix.

`#include <iostream>#include <cstdio>#include <cstdlib>#include <cstring>#include <set>#include <map>#include <queue>#include <string>#define maxn 200010#define lson l,m,rt<<1#define rson m+1,r,rt<<1|1using namespace std;typedef long long  ll;int a;struct segment{    int l,r;    int value;} son[maxn<<2];void PushUp(int rt){    son[rt].value=min(son[rt<<1].value,son[rt<<1|1].value);}void Build(int l,int r,int rt){    son[rt].l=l;    son[rt].r=r;    if(l==r)    {        son[rt].value=0;        return;    }    int m=(l+r)/2;    Build(lson);    Build(rson);    PushUp(rt);}void Update(int p,int rt){    if(son[rt].l==son[rt].r)    {        son[rt].value++;        return;    }    int m=(son[rt].l+son[rt].r)/2;    if(p<=m)        Update(p,rt<<1);    else        Update(p,rt<<1|1);    PushUp(rt);}int  Query(int l,int r,int rt){    if(son[rt].l==l&&son[rt].r==r)    {        return son[rt].value;    }    int ret=0;    int m=(son[rt].l+son[rt].r)/2;    if(r<=m)        ret=Query(l,r,rt<<1);    else if(l>m)        ret=Query(l,r,rt<<1|1);    else    {        ret=Query(lson);        ret=min(ret,Query(rson));    }    return ret;}int main(){    int n,k,x,ans=0;    bool flag=false;    scanf("%d%d",&n,&k);    Build(1,n+1,1);    for(int i=1;i<=n;i++)    {        scanf("%d",&x);        if(!flag)        {            x++;            a[x]++;            Update(x,1);            if(Query(1,x,1)<a[x]-k)            flag=true;            if(!flag) ans=i;        }    }    printf("%d\n",ans);    return 0;}`

Acdream 1427 nice sequence

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