Codeforces 221d D. Little Elephant and Array

二次联通门 : Codeforces 221d D. Little Elephant and Array

/*
    Codeforces 221d D. Little Elephant and Array

    题意 : 询问一段区间中出现次数等于自身的数的个数 

    正解是dp

    莫队水过， 作为我莫队的入门题
    myj的思路 66

    把所有需查询的区间排序

    当前查询区间的答案为上一个区间的答案通过多次的区间移动得出

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

#define Max 100005

void read (int &now)
{
    now = ;
    register char word = getchar ();
    bool temp = false;
    while (word < '' || word > '')
    {
        if (word == '-')
            temp = true;
        word = getchar ();
    }
    while (word >= '' && word <= '')
    {
        now = now *  + word - '';
        word = getchar ();
    }
    if (temp)
        now = -now;
}

int N, M;

int belong[Max];
struct Data
{
    int l, r;

    int ID;

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

int number[Max];

int K_Size;
int count[Max];
int rank_[Max];

Data query[Max];
int Answer[Max], Result;
int pos[Max];

incount void Updata (int now, int key)
{
    if (count[number[now]] == pos[now])
        Result--;
    count[number[now]] += key;
    if (count[number[now]] == pos[now])
        Result++;
}

int main (int argc, char *argv[])
{
    read (N);
    read (M);
    K_Size = sqrt (N);
    for (int i = ; i <= N; i++)
    {
        read (number[i]);
        rank_[i] = number[i];
        pos[i] = number[i];
        belong[i] = (i + ) / K_Size;
    }
    std :: sort (rank_ + , rank_ +  + N);
    int Size = std :: unique (rank_ + , rank_ +  + N) - rank_ - ;
    for (int i = ; i <= N; i++)
        number[i] = std :: lower_bound (rank_ + , rank_ +  + Size, number[i]) - rank_;
    for (int i = ; i <= M; i++)
    {
        read (query[i].l);
        read (query[i].r);
        query[i].ID = i;
    }
    std :: sort (query + , query +  + M);
    int l = , r = ;
    for (int cur = , now_1, now_2; cur <= M; cur++)
    {
        now_1 = query[cur].l;
        now_2 = query[cur].r;
        if (l < now_1)
            for (int i = l; i < now_1; i++)
                Updata (i, -);
        else
            for (int i = l - ; i >= now_1; i--)
                Updata (i, );
        if (r < now_2)
            for (int i = r + ; i <= now_2; i++)
                Updata (i, );
        else
            for (int i = r; i > now_2; i--)
                Updata (i, -);
        l = now_1;
        r = now_2;
        Answer[query[cur].ID] = Result;
    }
    for (int i = ; i <= M; i++)
        printf ("%d\n", Answer[i]);
    return ;
}