给定一个字符串s，长度为n，求s的所有子序列 1.子序列: 指一个字符串删掉部分字符（也可以不删）形成的字符串，可以是不连续的，比如"abcde"的子序列可以有"ace","ad"等等 2.将所有的子序列的结果返回为一个字符串数组 3.字符串里面可能有重复字符，但是返回的子序列不能有重复的子序列，比如"aab"的子序列只有"","a","aa","aab","ab","b"，不能存在2个相同的"ab" 4.返回字符串数组里面的顺序可以不唯一 数据范围: 要求:时间复杂度为
示例1
说明
返回["","b","a","ab"]也是可以的，视为正确，顺序不唯一
示例2
输出
["","b","bc","bcq","bq","c","cq","d","db","dbc","dbcq","dbq","dc","dcq","dq","q"]
示例3
输出
["","a","aa","aab","ab","b"]
说明
返回的字符串数组里面不能存在"ab","ab"这样2个相同的子序列
加载中...