bzoj3339（莫队+分块）

题面是截图不好发哇QAQ
同bzoj3585，甚至不用处理大于n的情况
这题时限20s我19.5s好险啊QAQ

#include<bits/stdc++.h>
using namespace std;
int n , Q , k;
int a[201000] , belong[201000];
int flag[201000];
int sum[500] , t;//k=块的大小 对数字进行分块 
struct data{
    int l , r , id;
}q[201000]; 
int read()
{
    int sum = 0;char c = getchar();bool flag = true;
    while( c < '0' || c > '9' ) {if(c == '-') flag = false;c = getchar();}
    while( c >= '0' && c <= '9' ) sum = sum * 10 + c - 48 , c = getchar();
    if(flag)  return sum;
     else return -sum;
}  
bool mycmp(data a,data b)
{
    return belong[a.l] < belong[b.l]||
         (belong[a.l] == belong[b.l] && a.r < b.r);
}
void init()
{
    n = read();Q = read();
    for(int i = 1;i <= n;++i) 
    {
        a[i] = read();
        if(a[i] > n) a[i] = n;
    } 
    for(int i = 1;i <= Q;++i)
        q[i].l = read() , q[i].r = read() , q[i].id = i;
    k = sqrt(n);
    if(k * k < n) t = k + 1,sum[t] = k*k + k - n; 
        else t = k;
    for(int i = 1,j = k,t = 1;i <= n;i += k,j += k,t++)
        if(j <= n) for(int x = i;x <= j;++x) belong[x] = t;
        else for(int x = i;x <= n;++x) belong[x] = t;
    sort(q + 1,q + Q + 1,mycmp); 
    return;
}
void add(int x)
{
    x = a[x];
    if(flag[x] == 0) sum[belong[x]]++;
    flag[x]++; 
    return;
}
void dele(int x)
{
    x = a[x];
    if(flag[x] == 1) sum[belong[x]]--;
    flag[x]--;
    return;
}
int print()
{
    if(!flag[0]) return 0;
    int i;
    for(i = 1;i <= t;++i)
        if(sum[i] != k)
            break;
    for(int j = (i - 1) * k + 1;i <= i * k;++i)
        if(!flag[i]) return i;
}
int out[201000];
void solve()
{
    int l = 1,r = 0;
    for(int i = 1;i <= Q;++i)
    {
        while(l > q[i].l) l-- , add(l);
        while(r < q[i].r) r++ , add(r);
        while(l < q[i].l) dele(l) , l++;
        while(r > q[i].r) dele(r) , r--; 
        out[q[i].id] = print();
    }
    for(int i = 1;i <= Q;++i)
        printf("%d\n",out[i]); 
    return;
}
int main()
{
    init();
    solve();
    return 0;
}