Java > String-3 > equalIsNot (CodingBat Solution)

Problem:

Given a string, return true if the number of appearances of "is" anywhere in the string is equal to the number of appearances of "not" anywhere in the string (case sensitive).

equalIsNot("This is not") → false
equalIsNot("This is notnot") → true
equalIsNot("noisxxnotyynotxisi") → true


Solution:

public boolean equalIsNot(String str) {
  int len = str.length();
  int not = 0;
  int is = 0;
  
  for (int i = 0; i < len; i++) {
    if (i < len - 2) {
      String tmp = str.substring(i,i+3);
      if (tmp.equals("not"))
        not++;
    }
    if (i < len - 1) {
      String tmp2 = str.substring(i,i+2);
      if (tmp2.equals("is"))
        is++;
    }
  }

  
  if (not == is)
    return true;
  else
    return false;

}

9 comments:

  1. lakohotJune 12, 2019 at 11:40 PM

    public boolean equalIsNot(String str) {
    int countIs = 0;
    int countNot = 0;
    str += " ";

    for (int i = 0; i < str.length() -2 ; i++) {
    if (str.substring(i, i+2).equals("is")) countIs++;
    if (str.substring(i, i+3).equals("not")) countNot++;
    }
    return (countIs == countNot);
    }

    ReplyDelete
    Replies
    1. LKayaMarch 7, 2022 at 12:42 PM

      This is so clever, thank you. I was struggling with a part. And this solved everything. "str += " ";"

      Delete
  2. Fedchenko IhorJune 21, 2019 at 12:24 AM

    public boolean equalIsNot(String str) {
    int diffLengthIs = str.length() - str.replaceAll("is", "").length();
    int diffLengthNot = str.length() - str.replaceAll("not", "").length();
    int countIs = diffLengthIs / 2;
    int countNot = diffLengthNot / 3;
    return countIs == countNot;
    }

    ReplyDelete
  3. AnonymousSeptember 13, 2020 at 3:45 PM

    public boolean equalIsNot(String str){
    return (str.length() - str.replaceAll("not", "").length()) / 3 == (str.length() - str.replaceAll("is", "" ).length()) / 2;
    }

    ReplyDelete
  4. AnonymousSeptember 13, 2020 at 3:46 PM

    public boolean equalIsNot(String str){
    return (str.length() - str.replaceAll("not", "").length()) / 3 == (str.length() - str.replaceAll("is", "" ).length()) / 2;
    }

    ReplyDelete
  5. AnonymousSeptember 13, 2020 at 3:46 PM

    public boolean equalIsNot(String str){
    return (str.length() - str.replaceAll("not", "").length()) / 3 == (str.length() - str.replaceAll("is", "" ).length()) / 2;
    }

    ReplyDelete
  6. UnknownNovember 25, 2020 at 3:55 AM

    public boolean equalIsNot(String str) {
    int m=0,n=0;
    for(int i=0;i<str.length();i++)
    {
    if(str.startsWith("is",i))
    m++;
    if(str.startsWith("not",i))
    n++;
    }
    return m==n;
    }

    ReplyDelete
  7. UnknownFebruary 4, 2021 at 1:26 AM

    public boolean equalIsNot(String str) {
    int ci = 0;
    int cn=0;
    int len = str.length();

    for(int i=0; i<len-1; i++){
    if(str.substring(i, i+2).equals("is")){
    ci++;
    }
    }
    for(int i=0; i<len-2; i++){
    if(str.substring(i, i+3).equals("not")){
    cn++;
    }
    }

    return ci==cn;
    }

    ReplyDelete
  8. UnknownFebruary 4, 2021 at 1:30 AM

    public boolean equalIsNot(String str) {
    int ci = 0;
    int cn=0;
    int len = str.length();

    for(int i=0; i<len; i++){
    if(i<len-1){
    if(str.substring(i, i+2).equals("is")){
    ci++;
    }
    }

    if(i<len-2){
    if(str.substring(i, i+3).equals("not")){
    cn++;
    }
    }
    }

    return ci==cn;
    }

    ReplyDelete