luogu P3709 大爷的字符串题

Posted 2020-09-21 ZlycerQan

二次联通门 : luogu P3709 大爷的字符串题

 

 

 

 

/*
    luogu P3709 大爷的字符串题 
 
 
    莫队
    看了半天题目 + 题解
    才弄懂了要求什么。。。
 
    维护两个数组
    一个记录数字i出现了几次
    一个记录出现了i次的有几个数。。
    

*/
#include <algorithm>
#include <cstdlib>
#include <cstdio>
#include <cmath>

#define Max 200090

void read (int &now)
{
    now = 0;
    register char word = getchar ();
    while (word < ‘0‘ || word > ‘9‘)
        word = getchar ();
    while (word >= ‘0‘ && word <= ‘9‘)
    {
        now = now * 10 + word - ‘0‘;
        word = getchar ();
    }
}

int belong[Max];

struct Query_Data
{
    int l, r;
    
    int Id;

    bool operator < (const Query_Data &now) const
    {
        if (belong[this->l] == belong[now.l])
            return this->r < now.r;
        return belong[this->l] < belong[now.l];
    }
};

int number[Max];
int N, M;

int count[Max];
int Answer[Max], Result;

Query_Data query[Max];
int __rank[Max];
int __count[Max];

inline void Updata (int now, bool type)
{
    if (type)
    {
        if (count[number[now]] == Result)
            Result ++;
        __count[count[number[now]]] --;
        ++ count[number[now]];
        __count[count[number[now]]] ++;
    }
    else
    {
        if (count[number[now]] == Result && __count[count[number[now]]] == 1)
            Result --;
        __count[count[number[now]]] --;
        count[number[now]] --;
        ++ __count[count[number[now]]];
    }
}

int main (int argc, char *argv[])
{
    read (N);
    read (M);
    int K_Size = sqrt (N);
    for (int i = 1; i <= N; i ++)
    {
        read (number[i]);
        __rank[i] = number[i];
        belong[i] = (i + 1) / K_Size;
    }
    std :: sort (__rank + 1, __rank + 1 + N);
    int Size = std :: unique (__rank + 1, __rank + 1 + N) - __rank - 1;
    for (int i = 1; i <= N; i ++)
        number[i] = std :: lower_bound (__rank + 1, __rank + 1 + Size, number[i]) - __rank;
    for (int i = 1; i <= M; i ++)
    {
        read (query[i].l);
        read (query[i].r);
        query[i].Id = i;
    }
    std :: sort (query + 1, query + 1 + M);
    int l = 1, r = 0;
    for (int i = 1; i <= M; i ++)
    {
        while (l < query[i].l)
            Updata (l ++, false);
        while (l > query[i].l)
            Updata (-- l, true);
        while (r < query[i].r)
            Updata (++ r, true);
        while (r > query[i].r)
            Updata (r --, false);
        Answer[query[i].Id] = Result;
    }
    for (int i = 1; i <= M; i ++)
        printf ("%d\n", -Answer[i]);
    //system ("pause");
    return 0;
}