v2ex_288684.py

# coding: utf-8

input_data = [
    {
        "title": "WTF?",
        "data_1": "5525577",
        "parentid": "0",
        "key": "7612"
    }, {
        "title": "用户管理",
        "data_1": "552559277",
        "parentid": "7612",
        "key": "7667"
    }, {
        "title": "开户",
        "data_1": "",
        "parentid": "7612",
        "key": "7668"
    }, {
        "title": "用户资料修改",
        "data_1": "552559279",
        "parentid": "7612",
        "key": "7669"
    }, {
        "title": "密码修改",
        "data_1": "5555279",
        "parentid": "7669",
        "key": "76691"
    }, {
        "title": "用户名修改",
        "data_1": "55279",
        "parentid": "7669",
        "key": "76692"
    },

]


def main():
    dct = {}
    reverse_dct = {}
    for item in input_data:
        if "data_1" not in item:
            continue
        parent = item["parentid"]
        current = item["key"]
        dct.setdefault(parent, []).append(current)
        reverse_dct[current] = parent

    # find root
    root = input_data[0]["key"]
    while root in reverse_dct:
        root = reverse_dct[root]
    root = dct[root][0]

    print "root: %s" % root
    # dfs
    stack = [(root, 0)]
    while stack:
        curr, indent = stack.pop()
        print " " * indent, curr
        for child_id in dct.get(curr, []):
            stack.append((child_id, indent + 2))


if __name__ == '__main__':
    main()