Concatenate words in such a way as to obtain the longest possible sub-string of the same letter












1












$begingroup$



An array of N words is given. Each word consists of small letters
('a'- 'z'). Our goal is to concatenate the words in such a way as to
obtain a single word with the longest possible sub-string composed of
one particular letter. Find the length of such a sub-string.





  • Examples:


    1. Given N=3 and words=['aabb','aaaa','bbab'], your function should return 6. One of the best concatenations is
      words[1]+words[0]+words[2]='aaaaaabbbbab'. The longest sub-string is
      composed of the letter 'a' and its length is 6.

    2. Given N=3 and words=['xxbxx','xbx','x'], your function should return 4. One of the best concatenations is
      words[0]+words[2]+words[1]='xxbxxxxbx'. The longest sub-string is
      composed of letter 'x' and its length is 4.




public class DailyCodingProblem4 {

public static void main(String args) {
String arr = { "aabb", "aaaa", "bbab" };
int res = solution(arr);
System.out.println(res);

String arr2 = { "xxbxx", "xbx", "x" };
res = solution(arr2);
System.out.println(res);
}

private static int solution(String arr) {
Map<Integer, Integer> prefix = new HashMap<>();
Map<Integer, Integer> suffix = new HashMap<>();
Map<Integer, Integer> both = new HashMap<>();
for (int i = 0; i < arr.length; i++) {
String word = arr[i];
int j = 1;
while (j < word.length() && word.charAt(0) == word.charAt(j)) {
j++;
}
int key = word.charAt(0);
if (j == word.length()) {
if (both.containsKey(key)) {
Integer temp = both.get(key);
if (j > temp) {
both.put(key, j);
}
} else {
both.put(key, j);
}
} else {
if (suffix.containsKey(key)) {
Integer temp = suffix.get(key);
if (j > temp) {
suffix.put(key, j);
}
} else {
suffix.put(key, j);
}

j = word.length() - 1;

while (j > 0 && word.charAt(word.length() - 1) == word.charAt(j - 1)) {
j--;
}

key = word.charAt(word.length() - 1);
if (prefix.containsKey(key)) {
Integer temp = prefix.get(key);
if (word.length() - j > temp) {
prefix.put(key, word.length() - j);
}
} else {
prefix.put(key, word.length() - j);
}
}
}
int res = 0;
for (Integer key : prefix.keySet()) {
if (suffix.containsKey(key)) {
int temp = prefix.get(key) + suffix.get(key);
if (temp > res) {
res = temp;
}
}

}

for (Integer key : suffix.keySet()) {
if (prefix.containsKey(key)) {
int temp = prefix.get(key) + suffix.get(key);
if (temp > res) {
res = temp;
}
}

}

for (Integer key : both.keySet()) {
if (prefix.containsKey(key)) {
int temp = prefix.get(key) + both.get(key);
if (temp > res) {
res = temp;
}
}
if (suffix.containsKey(key)) {
int temp = both.get(key) + suffix.get(key);
if (temp > res) {
res = temp;
}
}
}

return res;
}
}


Is there a better approach to solve the above problem? Is there something I can improve on?










share|improve this question











$endgroup$

















    1












    $begingroup$



    An array of N words is given. Each word consists of small letters
    ('a'- 'z'). Our goal is to concatenate the words in such a way as to
    obtain a single word with the longest possible sub-string composed of
    one particular letter. Find the length of such a sub-string.





    • Examples:


      1. Given N=3 and words=['aabb','aaaa','bbab'], your function should return 6. One of the best concatenations is
        words[1]+words[0]+words[2]='aaaaaabbbbab'. The longest sub-string is
        composed of the letter 'a' and its length is 6.

      2. Given N=3 and words=['xxbxx','xbx','x'], your function should return 4. One of the best concatenations is
        words[0]+words[2]+words[1]='xxbxxxxbx'. The longest sub-string is
        composed of letter 'x' and its length is 4.




    public class DailyCodingProblem4 {

    public static void main(String args) {
    String arr = { "aabb", "aaaa", "bbab" };
    int res = solution(arr);
    System.out.println(res);

    String arr2 = { "xxbxx", "xbx", "x" };
    res = solution(arr2);
    System.out.println(res);
    }

    private static int solution(String arr) {
    Map<Integer, Integer> prefix = new HashMap<>();
    Map<Integer, Integer> suffix = new HashMap<>();
    Map<Integer, Integer> both = new HashMap<>();
    for (int i = 0; i < arr.length; i++) {
    String word = arr[i];
    int j = 1;
    while (j < word.length() && word.charAt(0) == word.charAt(j)) {
    j++;
    }
    int key = word.charAt(0);
    if (j == word.length()) {
    if (both.containsKey(key)) {
    Integer temp = both.get(key);
    if (j > temp) {
    both.put(key, j);
    }
    } else {
    both.put(key, j);
    }
    } else {
    if (suffix.containsKey(key)) {
    Integer temp = suffix.get(key);
    if (j > temp) {
    suffix.put(key, j);
    }
    } else {
    suffix.put(key, j);
    }

    j = word.length() - 1;

    while (j > 0 && word.charAt(word.length() - 1) == word.charAt(j - 1)) {
    j--;
    }

    key = word.charAt(word.length() - 1);
    if (prefix.containsKey(key)) {
    Integer temp = prefix.get(key);
    if (word.length() - j > temp) {
    prefix.put(key, word.length() - j);
    }
    } else {
    prefix.put(key, word.length() - j);
    }
    }
    }
    int res = 0;
    for (Integer key : prefix.keySet()) {
    if (suffix.containsKey(key)) {
    int temp = prefix.get(key) + suffix.get(key);
    if (temp > res) {
    res = temp;
    }
    }

    }

    for (Integer key : suffix.keySet()) {
    if (prefix.containsKey(key)) {
    int temp = prefix.get(key) + suffix.get(key);
    if (temp > res) {
    res = temp;
    }
    }

    }

    for (Integer key : both.keySet()) {
    if (prefix.containsKey(key)) {
    int temp = prefix.get(key) + both.get(key);
    if (temp > res) {
    res = temp;
    }
    }
    if (suffix.containsKey(key)) {
    int temp = both.get(key) + suffix.get(key);
    if (temp > res) {
    res = temp;
    }
    }
    }

    return res;
    }
    }


    Is there a better approach to solve the above problem? Is there something I can improve on?










    share|improve this question











    $endgroup$















      1












      1








      1





      $begingroup$



      An array of N words is given. Each word consists of small letters
      ('a'- 'z'). Our goal is to concatenate the words in such a way as to
      obtain a single word with the longest possible sub-string composed of
      one particular letter. Find the length of such a sub-string.





      • Examples:


        1. Given N=3 and words=['aabb','aaaa','bbab'], your function should return 6. One of the best concatenations is
          words[1]+words[0]+words[2]='aaaaaabbbbab'. The longest sub-string is
          composed of the letter 'a' and its length is 6.

        2. Given N=3 and words=['xxbxx','xbx','x'], your function should return 4. One of the best concatenations is
          words[0]+words[2]+words[1]='xxbxxxxbx'. The longest sub-string is
          composed of letter 'x' and its length is 4.




      public class DailyCodingProblem4 {

      public static void main(String args) {
      String arr = { "aabb", "aaaa", "bbab" };
      int res = solution(arr);
      System.out.println(res);

      String arr2 = { "xxbxx", "xbx", "x" };
      res = solution(arr2);
      System.out.println(res);
      }

      private static int solution(String arr) {
      Map<Integer, Integer> prefix = new HashMap<>();
      Map<Integer, Integer> suffix = new HashMap<>();
      Map<Integer, Integer> both = new HashMap<>();
      for (int i = 0; i < arr.length; i++) {
      String word = arr[i];
      int j = 1;
      while (j < word.length() && word.charAt(0) == word.charAt(j)) {
      j++;
      }
      int key = word.charAt(0);
      if (j == word.length()) {
      if (both.containsKey(key)) {
      Integer temp = both.get(key);
      if (j > temp) {
      both.put(key, j);
      }
      } else {
      both.put(key, j);
      }
      } else {
      if (suffix.containsKey(key)) {
      Integer temp = suffix.get(key);
      if (j > temp) {
      suffix.put(key, j);
      }
      } else {
      suffix.put(key, j);
      }

      j = word.length() - 1;

      while (j > 0 && word.charAt(word.length() - 1) == word.charAt(j - 1)) {
      j--;
      }

      key = word.charAt(word.length() - 1);
      if (prefix.containsKey(key)) {
      Integer temp = prefix.get(key);
      if (word.length() - j > temp) {
      prefix.put(key, word.length() - j);
      }
      } else {
      prefix.put(key, word.length() - j);
      }
      }
      }
      int res = 0;
      for (Integer key : prefix.keySet()) {
      if (suffix.containsKey(key)) {
      int temp = prefix.get(key) + suffix.get(key);
      if (temp > res) {
      res = temp;
      }
      }

      }

      for (Integer key : suffix.keySet()) {
      if (prefix.containsKey(key)) {
      int temp = prefix.get(key) + suffix.get(key);
      if (temp > res) {
      res = temp;
      }
      }

      }

      for (Integer key : both.keySet()) {
      if (prefix.containsKey(key)) {
      int temp = prefix.get(key) + both.get(key);
      if (temp > res) {
      res = temp;
      }
      }
      if (suffix.containsKey(key)) {
      int temp = both.get(key) + suffix.get(key);
      if (temp > res) {
      res = temp;
      }
      }
      }

      return res;
      }
      }


      Is there a better approach to solve the above problem? Is there something I can improve on?










      share|improve this question











      $endgroup$





      An array of N words is given. Each word consists of small letters
      ('a'- 'z'). Our goal is to concatenate the words in such a way as to
      obtain a single word with the longest possible sub-string composed of
      one particular letter. Find the length of such a sub-string.





      • Examples:


        1. Given N=3 and words=['aabb','aaaa','bbab'], your function should return 6. One of the best concatenations is
          words[1]+words[0]+words[2]='aaaaaabbbbab'. The longest sub-string is
          composed of the letter 'a' and its length is 6.

        2. Given N=3 and words=['xxbxx','xbx','x'], your function should return 4. One of the best concatenations is
          words[0]+words[2]+words[1]='xxbxxxxbx'. The longest sub-string is
          composed of letter 'x' and its length is 4.




      public class DailyCodingProblem4 {

      public static void main(String args) {
      String arr = { "aabb", "aaaa", "bbab" };
      int res = solution(arr);
      System.out.println(res);

      String arr2 = { "xxbxx", "xbx", "x" };
      res = solution(arr2);
      System.out.println(res);
      }

      private static int solution(String arr) {
      Map<Integer, Integer> prefix = new HashMap<>();
      Map<Integer, Integer> suffix = new HashMap<>();
      Map<Integer, Integer> both = new HashMap<>();
      for (int i = 0; i < arr.length; i++) {
      String word = arr[i];
      int j = 1;
      while (j < word.length() && word.charAt(0) == word.charAt(j)) {
      j++;
      }
      int key = word.charAt(0);
      if (j == word.length()) {
      if (both.containsKey(key)) {
      Integer temp = both.get(key);
      if (j > temp) {
      both.put(key, j);
      }
      } else {
      both.put(key, j);
      }
      } else {
      if (suffix.containsKey(key)) {
      Integer temp = suffix.get(key);
      if (j > temp) {
      suffix.put(key, j);
      }
      } else {
      suffix.put(key, j);
      }

      j = word.length() - 1;

      while (j > 0 && word.charAt(word.length() - 1) == word.charAt(j - 1)) {
      j--;
      }

      key = word.charAt(word.length() - 1);
      if (prefix.containsKey(key)) {
      Integer temp = prefix.get(key);
      if (word.length() - j > temp) {
      prefix.put(key, word.length() - j);
      }
      } else {
      prefix.put(key, word.length() - j);
      }
      }
      }
      int res = 0;
      for (Integer key : prefix.keySet()) {
      if (suffix.containsKey(key)) {
      int temp = prefix.get(key) + suffix.get(key);
      if (temp > res) {
      res = temp;
      }
      }

      }

      for (Integer key : suffix.keySet()) {
      if (prefix.containsKey(key)) {
      int temp = prefix.get(key) + suffix.get(key);
      if (temp > res) {
      res = temp;
      }
      }

      }

      for (Integer key : both.keySet()) {
      if (prefix.containsKey(key)) {
      int temp = prefix.get(key) + both.get(key);
      if (temp > res) {
      res = temp;
      }
      }
      if (suffix.containsKey(key)) {
      int temp = both.get(key) + suffix.get(key);
      if (temp > res) {
      res = temp;
      }
      }
      }

      return res;
      }
      }


      Is there a better approach to solve the above problem? Is there something I can improve on?







      java algorithm strings programming-challenge






      share|improve this question















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