Thursday, December 12, 2013


The Question is

Problem Statement

     Fox Ciel received a string as a birthday present. However, the string was too long for her, so she decided to make it shorter by erasing some characters.

The erasing process will look as follows:
  1. Find the smallest i such that the i-th character and the (i+1)-th character of the string are same.
  2. If there is no such i, end the process.
  3. Remove the i-th and the (i+1)-th character of the string, and repeat from 1.

For example, if she receives "cieeilll", she will change the string as follows: "cieeilll" -> "ciilll" -> "clll" -> "cl". You are given a String s. Return the string she will get after she erases characters as described above.


Class: ErasingCharacters
Method: simulate
Parameters: String
Returns: String
Method signature: String simulate(String s)
(be sure your method is public)


Time limit (s): 2.000
Memory limit (MB): 64


- s will contain between 1 and 50 characters, inclusive.
- Each character in s will be a lowercase letter ('a'-'z').


Returns: "cl"
This is the example from the statement.
Returns: "topcoder"
She won't erase any characters at all.
Returns: ""
Returns: "bacbaca"
Returns: "l"

My Solution is Below

public static String simulate(String str){
  int start =0;
  while(str.length()-1 >start){
   char firstChar = str.charAt(start);
//   System.out.println(firstChar + " : fisrt");
   char nextChar = str.charAt(start+1);
//   System.out.println(nextChar +" : next");
   if(firstChar == nextChar){
    str = str.substring(0, start) + str.substring(start+2, str.length());
//    System.out.println("complete:" + str);
    if(start !=0){
//  System.out.println(str);
  return str;

## Access Logic ##

my access is below but i don't think this is a good sample

because i just got 144point / 250 point

so other soultions are better than my solution

i attached other solution after my solution

first point is c
first+1 point is i

c and i is differenct so first point will be 2

first point is i
first+1 point is e

c and i is differenct so first point will be 3

firtst point e
first+1 point is e

e and e is the same so cut before first point "ci" and cut after firstPoint +1 to end "ill"
and concat before string and after string

this will be ciill

first point changed first-1

Otheres are Below

public static String simulate(String s){
  for(int i=0; i<s.length()-1 i++){
    if(s.charAT(i) == s.charAT(i+1)){
     s= s.substring(0, i) + s.substring(i+2, s.length);

sombody use StringBuffer.delete

and sombody use Stack

many different way i learend from topcoder --V

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