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package string;

/**

* Created by gouthamvidyapradhan on 12/04/2018. Given an array of characters, compress it in-place.

*

* <p>The length after compression must always be smaller than or equal to the original array.

*

* <p>Every element of the array should be a character (not int) of length 1.

*

* <p>After you are done modifying the input array in-place, return the new length of the array.

*

* <p>Follow up: Could you solve it using only O(1) extra space?

*

* <p>Example 1: Input: ["a","a","b","b","c","c","c"]

*

* <p>Output: Return 6, and the first 6 characters of the input array should be:

* ["a","2","b","2","c","3"]

*

* <p>Explanation: "aa" is replaced by "a2". "bb" is replaced by "b2". "ccc" is replaced by "c3".

* Example 2: Input: ["a"]

*

* <p>Output: Return 1, and the first 1 characters of the input array should be: ["a"]

*

* <p>Explanation: Nothing is replaced. Example 3: Input:

* ["a","b","b","b","b","b","b","b","b","b","b","b","b"]

*

* <p>Output: Return 4, and the first 4 characters of the input array should be: ["a","b","1","2"].

*

* <p>Explanation: Since the character "a" does not repeat, it is not compressed. "bbbbbbbbbbbb" is

* replaced by "b12". Notice each digit has it's own entry in the array. Note: All characters have

* an ASCII value in [35, 126]. 1 <= len(chars) <= 1000.

*

* <p>Solution O(N) time complexity and O(1) space complexity. Maintain read and write pointers.

* Read from read pointer and increment count when a repetition is found, when there is no

* repetition write the count value using write pointer.

*/

public class StringCompression {

/**

* Main method

*

* @param args

* @throws Exception

*/

public static void main(String[] args) throws Exception {

char[] A = {'a', 'a', 'b', 'b', 'c', 'c', 'c'};

System.out.println(new StringCompression().compress(A));

}

public int compress(char[] chars) {

int count = 0;

int i = 0;

int p = 0;

for (int j = 0; j < chars.length; j++) {

if (chars[i] == chars[j]) {

count++;

} else {

chars[p] = chars[i];

p++;

if (count > 1) {

String countStr = String.valueOf(count);

for (int l = 0; l < countStr.length(); l++) {

chars[p++] = countStr.charAt(l);

}

}

i = j;

count = 1;

}

}

chars[p] = chars[i];

p++;

if (count > 1) {

String countStr = String.valueOf(count);

for (int l = 0; l < countStr.length(); l++) {

chars[p++] = countStr.charAt(l);

}

}

return p;

}

}