백준 2805

package baekjoon.이분탐색;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;

class Main2805 {

   static int N, M;
   static int[] h;



   private static boolean determination(int H) {
      long sum = 0;
      for (int i = 1; i <= N; i++) {
         if (h[i] > H) {
            sum += h[i] - H;
         }
      }
      return sum >= M;
   }

   private static void go() {
      long L = 0, R = 2_000_000_000, ans = 0;

      while (L <= R) {
         long mid = (L + R) / 2;
         if (determination((int)mid)) {
            ans = mid;
            L = mid + 1;
         } else {
            R = mid - 1;
         }
      }
      System.out.println(ans);
   }

   public static void main(String[] args) throws Exception {
      input();
      go();
   }

   private static void input() throws IOException {
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      StringTokenizer st = new StringTokenizer(br.readLine());
      N = Integer.parseInt(st.nextToken());
      M = Integer.parseInt(st.nextToken());
      h = new int[N + 1];
      st = new StringTokenizer(br.readLine());
      for (int i = 1; i <= N; i++) {
         h[i] = Integer.parseInt(st.nextToken());
      }
      Arrays.sort(h);
   }
}