算法1

(二分) $O(nlogn)$

上界是1e9+1e9=2e9 最小是原数组中位数

二分即可

python 代码

n, k = map(int, input().split())
arr = list(map(int, input().split()))

arr.sort()
l, r = arr[n//2], 2e9

def check(m):
    res = 0
    for i in range(n//2, n):
        if arr[i] < m:
            res += (m-arr[i])
    return res<=k

while l<r:
    mid = (l+r+1)//2
    if check(mid):
        l = mid 
    else:
        r  = mid - 1
print(int(r))