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Problem Statement for "MiddleCode"

Problem Statement

Hero is learning a new algorithm to encode a string. You are given a String s that consists of lowercase letters only. Your task is to simulate the algorithm described below on this string, so that Hero can see how it works.

The algorithm starts with a given input string s and an empty output string t. The execution of the algorithm consists of multiple steps. In each step, s and t are modified as follows:
  • If the length of s is odd, the middle character of s is added to the end of t, and then deleted from s.
  • If the length of s is even, the two characters in the middle of s are compared. The smaller one of them (either one in case of a tie) is added to the end of t, and then deleted from s.
If after some step the string s is empty, the algorithm terminates. The output of the algorithm is the final string t.

Return the String t that will be produced by the above algorithm for the given String s.

Definition

Class:
MiddleCode
Method:
encode
Parameters:
String
Returns:
String
Method signature:
String encode(String s)
(be sure your method is public)

Notes

  • When comparing letters, the smaller one is the one earlier in the alphabet - i.e., the character with the smaller ASCII code.

Constraints

  • s will contain between 1 and 50 characters, inclusive.
  • Each character in s will be a lowercase letter ('a'-'z').

Examples

  1. "word"

    Returns: "ordw"

    In the first step, 'o' is smaller than 'r', thus 'o' is selected. After the first step: s="wrd", t="o". After the second step: s="wd", t="or". In the third step, 'w' is greater than 'd', thus 'd' is selected. After the third step: s="w", t="ord". After the fourth step: s="", t="ordw", and the algorithm terminates.

  2. "aaaaa"

    Returns: "aaaaa"

  3. "abacaba"

    Returns: "caabbaa"

  4. "shjegr"

    Returns: "ejghrs"

  5. "adafaaaadafawafwfasdaa"

    Returns: "afawadafawafaafsadadaa"

  6. "bbaab"

    Returns: "aabbb"

  7. "bbaabaaaaa"

    Returns: "abaaaaabab"

  8. "bbaabaaaaabbbbbbbaba"

    Returns: "abababababbbabaabbab"

  9. "bbaabaaaaabbbbbbbababaabaabaabbabab"

    Returns: "abbabbbababbbabaaabaaaaabbbaaababbb"

  10. "bbaabaaaaabbbbbbbababaabaabaabbabababbbabbabbabbba"

    Returns: "aabbaaaabbababababbbabbbbbbbabababaaabababababbbab"

  11. "ggffgfffffgggggggfgfgffgffgffggfgfgfgggfggfggfgggf"

    Returns: "ffggffffggfgfgfgfgggfgggggggfgfgfgfffgfgfgfgfgggfg"

  12. "ghjfjjiihjffghggfhhggjhihhggifhggijhhjfjighiijggii"

    Returns: "hhgighijfgghghghfigjghhhgjfffjijghhiiiijjjfggjhigi"

  13. "ghjfjjiihjffghggfhhggjhihhggifhggijhhjfj"

    Returns: "gghjhhfighghghggfiffhjghgiiijjhjfhjjfhgj"

  14. "gmjfojnnhjkkgmggkhmlgjhihhglnkmlgnohmokj"

    Returns: "gljmhhikghghgmglknkkjmhlgnnnjohofmjokmgj"

  15. "phqghumeaylnlfdxfircvscxggbwkfnqduxwfnfozvsrtkjpre"

    Returns: "ggbxcwksfvcnqrdifuxxdwfflnfnloyzavesmrtuhkgjpqhrep"

  16. "phqghumeaylnlfdxfircvscxggbwkfnqduxwfnfoz"

    Returns: "vcscrixfggxbdfwklfnlnqyadeumxuwfhgnfqhopz"

  17. "phqghumeaylnlfdxfircvscxg"

    Returns: "lfndlxyafeimrcuhvgscqhxgp"

  18. "phqghumeay"

    Returns: "hugmeqahpy"

  19. "phqghu"

    Returns: "gqhhpu"

  20. "kfkjhgjejkejkkefkeiigghkjkjjkffjfgeijeihhiigjgeiff"

    Returns: "jkjkhjgkfgfiijefgkefeijkekijehhkijeigjgjghejikfffk"

  21. "fhkifikkgefffhfhhkhilikfikjikllkhgjehhhklhgjfejlji"

    Returns: "ikfjikikllilhkhkghhjefhhfhfhfkelghgkjkfiefijklhjfi"

  22. "jmlimfhelgmglkljlmheekjeilkjmjgegekimflhgkghkghlgf"

    Returns: "ilekjjkmejegehgmeljkilkmflglhmggkleghhfkgmhillgmfj"

  23. "mnnfljjofelljmklhlngllmoklmjklgfnooginljiljklejeji"

    Returns: "klmojmklllggfnlnhologkimjnlljleifljojkjlelfjenjnim"

  24. "pgiosihhlsjjfqfpogqkknghllkpmjgkphnlgionmkghhskfmr"

    Returns: "llhkgpmnjkgkkqgphonpflgqfijojnmsklghhhhisskofigmpr"

  25. "ljosouhuefoomsuthmurkfnehkrutjletqujsefelpmjokpoue"

    Returns: "hkernuftjklreumthqtujussemfoeoflepmuhjoukopsoojuel"

  26. "abba"

    Returns: "bbaa"

  27. "x"

    Returns: "x"

  28. "worde"

    Returns: "rdoew"

  29. "ab"

    Returns: "ab"

  30. "abc"

    Returns: "bac"

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