Java P1873 [COCI 2011/2012 #5] EKO / 砍树

import java.util.*;
import java.io.*;
public class Main {
	static int N = 1000010;
	
	static int a[] = new int[N]; // 学校分数线
	static int n, need;
	
	static boolean check(int x) {
		long s = 0;
		for(int i = 0; i < n; i ++ ) {
			s += Math.max(a[i] - x, 0);
		}
		return s >= need;
	}
	
    public static void main(String[] args){
        Reader sc = new Reader();
        n = sc.nextInt();
        need = sc.nextInt();
        for(int i = 0; i < n; i ++ )
        	a[i] = sc.nextInt();
        
        int l = 0, r = (int)1e9;
        while(l < r) {
        	int mid = l + r + 1 >> 1;
        	if(check(mid))
        		l = mid;
        	else r = mid - 1;
        }
        
        System.out.println(l);
    }
    static class Reader {
        public BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        public StreamTokenizer st = new StreamTokenizer(br);

        public void token() {
            try {
                st.nextToken();
            } catch (IOException e) {}
        }

        public int nextInt() {
            token();
            return (int)st.nval;
        }

        public String next() {
            token();
            return st.sval;
        }
    }
}