为什么用algri库就TLE了

#include<iostream>
#include<algorithm>
using namespace std;
int N,Q;
const int MAXN = 1e6+5;
int a[MAXN];
int main()
{
    cin>>N>>Q;
    for(int i = 1; i <= N; i++){
        int tmp = 0;
        cin>>tmp;
        a[i] = tmp;
    }
    
    for(int i = 1;i <= Q; i++){
        int x,y;
        cin>>x>>y;
        sort(a+1, a + 1 + N);
        int ans = upper_bound(a + 1, a + 1 + N,y) - lower_bound(a + 1, a + N + 1, x);
        cout<<ans<<endl;
    }
    return 0 ;
}