題意：對任意區間排序，問你第x個位置上的數的位置是否發生變化

在得知n^2能過這個題我的內心是崩潰的.........

#include <stdio.h>  
#include <string.h>  
#include <algorithm>  
#include <iostream>  
using namespace std;  
const int maxn=30005;  
int aa[maxn],bb[maxn];
int C[maxn],ans[maxn];  
int n,m;  
  
int lowbit(int x)  
{  
    return x&(-x);  
}  
  
int sum(int x)  
{  
    int ret=0;  
    while(x>0)  
    {  
        ret+=C[x];  
        x-=lowbit(x);  
    }  
    return ret;  
}  
  
void add(int x,int d)  
{  
    while(x<=n)  
    {  
        C[x]+=d;  
        x+=lowbit(x);  
    }  
}  
  
struct node  
{  
    int id,num;  
    bool operator < (const node &other) const  
    {  
        return num < other.num;  
    }  
}a[maxn];  
struct note  
{  
    int l,r,id,value;  
    bool operator < (const note &other)const  
    {  
        return value <other.value;  
    }  
}b[maxn];  
  
int main()  
{   
        scanf("%d%d",&n,&m);  
        for(int i=1;i<=n;i++)  
        {  
            int x;  
            scanf("%d",&a[i].num);  
            a[i].id=i;  
        }  
        for(int i=1;i<=m;i++)  
        {  
            scanf("%d%d%d",&b[i].l,&b[i].r,&b[i].value); 
			bb[i]=b[i].value;
			b[i].value=a[b[i].value].num;
            b[i].id=i; 
			aa[i]=b[i].l;
        }  
        sort(a+1,a+n+1);  
        sort(b+1,b+m+1);  
       // memset(C,0,sizeof(C));  
        int k=1;  
        for(int i=1;i<=m;i++)  
        {  
            while(k<=n&&a[k].num<b[i].value)  
            {  
                add(a[k].id,1);  
                k++;  
            }  
            ans[b[i].id]=sum(b[i].r)-sum(b[i].l-1);  
        }   
        for(int i=1;i<=m;i++)  
        {  
			if(ans[i]!=bb[i]-aa[i])
				printf("No\n");
			else
				printf("Yes\n");
           // printf("%d\n",ans[i]);  
        }    
    return 0;  
}