StringCompression.java

package easy;
/**
 * ClassName: StringCompression.java
 * Author: chenyiAlone
 * Create Time: 2019/8/24 22:33
 * Description: No.443 String Compression
 *
 *Given an array of characters, compress it in-place.
 *
 * The length after compression must always be smaller than or equal to the original array.
 *
 * Every element of the array should be a character (not int) of length 1.
 *
 * After you are done modifying the input array in-place, return the new length of the array.
 *
 *
 * Follow up:
 * Could you solve it using only O(1) extra space?
 *
 *
 * Example 1:
 *
 * Input:
 * ["a","a","b","b","c","c","c"]
 *
 * Output:
 * Return 6, and the first 6 characters of the input array should be: ["a","2","b","2","c","3"]
 *
 */
public class StringCompression {
    public int compress(char[] chars) {
        int anchor = 0, write = 0;
        for (int read = 0; read < chars.length; read++) {
            if (read + 1 == chars.length || chars[read + 1] != chars[read]) {
                chars[write++] = chars[anchor];
                if (read > anchor) {
                    for (char c: ("" + (read - anchor + 1)).toCharArray()) {
                        chars[write++] = c;
                    }
                }
                anchor = read + 1;
            }
        }
        return write;
    }
}