题解 | #平均数为k的最长连续子数组#

import java.io.*;
import java.util.*;
import java.math.BigInteger;

public class Main {
    static int N =(int)(2e5+10);
    static int n;
    static long k;
    static long[] a = new long[N];

    static void solve() {
        n = in.nextInt(); k = in.nextLong();
        HashMap<Long,Integer> mp = new HashMap<>();
        mp.put(0L,0);
        long ans = -1;
        for(int i=1;i<=n;i++) {
            a[i] = in.nextLong();
            a[i] -= k;
            a[i] += a[i-1];
            if(!mp.containsKey(a[i])) {
                mp.put(a[i],i);
            }else {
                ans = Math.max(ans,i-mp.get(a[i]));
            }
        }
        out.println(ans);
    }

    public static void main(String[] args) {
        solve();
        out.flush();
    }

    static FastReader in = new FastReader();
    static PrintWriter out = new PrintWriter(System.out);

    static class FastReader {
        static BufferedReader br;
        static StringTokenizer st;

        FastReader() {
            br = new BufferedReader(new InputStreamReader(System.in));
        }

        String next() {
            String str = "";
            while (st == null || !st.hasMoreElements()) {
                try {
                    str = br.readLine();
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
                st = new StringTokenizer(str);
            }
            return st.nextToken();
        }

        int nextInt() {
            return Integer.parseInt(next());
        }

        double nextDouble() {
            return Double.parseDouble(next());
        }

        long nextLong() {
            return Long.parseLong(next());
        }
    }
}