思路：首先将数组从小到大排序，然后计算出中位数的值。然后遍历数组，对于每个元素x，计算表达式x-x0+1]- X＋K-1的值，找到与中位数差距最小的下标，并记录最大的下标。最后返回记录的最大下标即可。

代码实现：

def find_index(X, K): X.sort() n = len(X) mid = X[n // 2] diff = float('inf') max_index = -1 for i in range(n): res = X[i] - X[0] + 1 - X[i] + K - 1 cur_diff = abs(res - mid) if cur_diff < diff: diff = cur_diff max_index = i elif cur_diff == diff: max_index = max(max_index, i) return max_index + 1

测试

X = [1, 3, 5, 7, 9] K = 2 print(find_index(X, K)) # 输出