二分探索 「kを超える最初の場所」がright、「k以上の最初の場所」がleft python >>> import bisect >>> xs = [1, 2, 4, 4, 5] >>> [bisect.bisect_left(xs, x) for x in range(7)] [0, 0, 1, 2, 2, 4, 5] >>> [bisect.bisect_right(xs, x) for x in range(7)] [0, 1, 2, 2, 4, 5, 5] atcoder
