input ab2c3 output ababcababcababc String manipulation

/**
 * input happ3ymarri4geanive6sa6y9
 */
/**
 * input ab2c3
 * output ababcababcababc
 */
package com.codecreeks.solutions;

/**
 * @author Steffi
 *
 */
public class StringManipBuffer {

/**
* @param args
*/
public static void main(String[] args) {

long startTime = System.currentTimeMillis();

StringManipBuffer stringManip = new StringManipBuffer();
String output = stringManip.compute("ab9c9");
System.out.println(output);
Runtime runtime = Runtime.getRuntime();
        runtime.gc();
        long memory = runtime.totalMemory() - runtime.freeMemory();
        System.out.println("Used memory is KB: " + memory/1024);
        long stopTime = System.currentTimeMillis();
        long elapsedTime = stopTime - startTime;
        System.out.println(" Time Taken :"+elapsedTime);

}

private String compute(String input) {
StringBuffer sb = new StringBuffer();
char[] charInput = input.toCharArray();
for (Character ch : charInput) {
if (ch.isDigit(ch)) {
String str = loop(sb.toString(), (int) ch - 48);
sb.delete(0,sb.length());
sb.append(str);
} else {
sb.append(ch);
}
}

return sb.toString();
}

private String loop(String str, int count) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < count; i++) {
sb.append(str);
}
return sb.toString();
}

}

/**

 * input ab2c3

 * output ababcababcababc

 */

package com.codecreeks.solutions;

/**

 * @author Steffi

 *

 */

public class StringManip {

/**

* @param args

*/

public static void main(String[] args) {

long startTime = System.currentTimeMillis();

StringManip stringManip = new StringManip();

String output = stringManip.compute("ab9c9");

System.out.println(output);

Runtime runtime = Runtime.getRuntime();

        runtime.gc();

        long memory = runtime.totalMemory() - runtime.freeMemory();

        System.out.println("Used memory is KB: " + memory/1024);

        long stopTime = System.currentTimeMillis();

        long elapsedTime = stopTime - startTime;

        System.out.println(" Time Taken :"+elapsedTime);

}

private String compute(String input) {

StringBuilder sb = null;

char[] charInput = input.toCharArray();

for (Character ch : charInput) {

if (ch.isDigit(ch)) {

String str = loop(sb.toString(), (int) ch - 48);

sb = new StringBuilder(str);

} else {

if (null == sb) {

sb = new StringBuilder();

} 

sb.append(ch);

}

}

return sb.toString();

}

private String loop(String str, int count) {

StringBuilder sb = new StringBuilder();

for (int i = 0; i < count; i++) {

sb.append(str);

}

return sb.toString();

}

}

input ab2c3

ababcababcababc

Used memory is KB: 292

 Time Taken :6

ababcababcababc

Used memory is KB: 293

 Time Taken :8

input ab9c9

abababababababababcabababababababababcabababababababababcabababababababababcabababababababababcabababababababababcabababababababababcabababababababababcabababababababababc

Used memory is KB: 293

 Time Taken :7

abababababababababcabababababababababcabababababababababcabababababababababcabababababababababcabababababababababcabababababababababcabababababababababcabababababababababc

Used memory is KB: 293

 Time Taken :6