import java.util.Stack;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

/**

* @description:

* @Author: JachinDo

* @Date: 2019/10/21 20:45

*/

public class DecodingString {

public String decodeString(String s) {

Stack<String> stack = new Stack<>();

for(int i = 0; i < s.length(); i++){

char curr = s.charAt(i);

if (curr != ']') {

stack.push(String.valueOf(curr));

} else {

StringBuilder sb = new StringBuilder();

while(!"[".equals(stack.peek())){

sb.append(stack.pop());

}

stack.pop();

StringBuilder Num = new StringBuilder();

while (!stack.isEmpty() && stack.peek().charAt(0) >= '0' && stack.peek().charAt(0) <= '9') {

Num.append(stack.pop());

}

int repeatCount = Integer.parseInt(Num.reverse().toString());

String repeateString = sb.toString();

for (int j = 0; j < repeatCount; j++) {

// for (int k = 0; k < repeateString.length(); k++) {

// stack.push(String.valueOf(repeateString.charAt(k)));

// }

stack.push(repeateString);

}

}

}

StringBuilder res = new StringBuilder();

while (!stack.isEmpty()) {

res.append(stack.pop());

}

String resu = res.reverse().toString();

System.out.println(resu);

return resu;

}

}