Question

您将获得正负整数的列表跳转，表示正向或负向跳跃。

从索引0开始，您跳转到索引0+jump[0]。一般来说，如果你在索引k，你会跳转到索引k+jump[k]让我们说jumps[0]是2。索引变为2.假设jumps[2]为-1，索引将变为1。

编写函数list_jumps(jumps)，其中jumps是上述列表。如果索引永远不会离开输入列表的边界，则函数应返回字符串'cycle'，否则它必须返回'out-of-bounds'。起始索引始终为0.

dm=[3,0,0,-2]

def list_jump(jumps):
    xs=jumps
    xy=jumps
    max=len(xs)
    while(True):
        p = int(xs[0])
        print p
        for i in range (0,max,p):
            print i,"iii"
            p = xs[i]
            if xs[i]=="visited":
                return False
            else:
                xs[i]="visited"
            print xs
    return True

if list_jump(dm):
    print "not cycle"
else:
    print "cycle"

我真的不需要解决方案。我只是想知道错误是什么。

Answer 1

请注意，我只需创建一个集合seen并将每个索引添加到其中。

def list_jump(jumps):
    i = 0
    seen = {0}

    while True:
        try:
            i += jumps[i]
            if i < 0:
                # negative indices are legal, but we should exit if we have one.
                return "out-of-bounds"
        except IndexError:
            # we've escaped the list: non-cyclic!
            return "out-of-bounds"
        else:
            if i in seen:
                return "cycle"
            else:
                seen.add(i)

在列表中跳跃时出错

1 个答案: