落花人独立,微雨燕双飞.相寻梦里路,飞雨落花中.

//待测 #双向选择排序 a = int(input()) n = len(a) left = 0; right = n - 1 while left<right: minx = left; maxx = right for j in range(left, right + 1): if d[j]>d[maxx]: maxx = j if d[j]<d[minx]: minx = j if left != minx: d[left], d[mixx] = d[mixx], d[left] if right != maxx: if maxx == left: d[right], d[minx] = d[minx], d[right] else: d[right], d[maxx] = d[maxx], d[right]

//可行（低效）的二分找第一 d=[1, 2, 6, 6, 6, 6, 8, 10] left = 0; right = len(d) - 1; key = 6; while left <= right: m = (left + right) // 2 if d[m] < key: left = m + 1 elif d[m] > key: right = m - 1 else: while d[m] == key: m -= 1 break if left > right: print('未找到') else: print('找到，位置：', m + 1)

//优化后（非双重循环）