Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Interview Coding Questions
// Check If a string has all unique characters, without using additional data structure.
func isUnique(string: String) -> Bool {
// what type of characters // if ascii characters
if string.characters.count > 128 {
return true
}
var cIdx = 0
for c in string.characters {
var ccIdx = 0
for cc in string.characters {
if cIdx != ccIdx && c == cc {
print("\(c)==\(cc)")
return true
}
ccIdx = ccIdx + 1
}
cIdx = cIdx + 1
}
return false
}
print(isUnique("qwertyuiopasdfghjklzxcv1234567890-=!@#$%^&*()_+<>:{}|~`,./;'bnm,."))
// Trim whitespace characters from beginning, end of the string, and more than one space in between.
func trimming(string : String) -> String? {
var str: String = ""
var isCarShuru = false
var isMidSpace = false
for i in 0..<string.characters.count {
let char = Array(string.characters)[i]
if char != " " {
if isMidSpace {
str = str + " " + String(char)
isMidSpace = false
}
else {
str = str + String(char)
}
isCarShuru = true
}
else {
if isCarShuru && isMidSpace == false {
isMidSpace = true
}
}
}
return str
}
print(trimming(" Roch the world "))
// Check Palindrome or a permutation of palindrome
func isPalindrome(string: String) -> Bool {
var oddCount = 0
var arrDone = Array(count: string.characters.count, repeatedValue: "Yo")
for c1 in string.characters {
var isSame = false
for cOld in arrDone {
if cOld == String(c1) {
isSame = true
}
}
if !isSame {
var isOdd = false
for c2 in string.characters {
if c1 == c2 {
isOdd = !isOdd
}
}
if isOdd {
oddCount = oddCount + 1
if oddCount == 2 {
return false;
}
}
arrDone.append(String(c1))
}
}
return true
}
print(isPalindrome("aibohphobia"))
print(isPalindrome("palindrome"))
// Check Permutation: given two string, if one is a permutation to other.
func isPermutation(string1: String, of string2: String) -> Bool {
if (string1.characters.count != string2.characters.count) {
return false
}
var charArray = Array(count: string1.characters.count, repeatedValue: "Yo")
for char1 in string1.characters {
var isFound = false
for c0 in charArray {
if String(char1) == c0 {
isFound = true
break
}
}
if !isFound {
var char1Count = 0
for c in string1.characters {
if c == char1 {
char1Count = char1Count + 1;
}
}
var char2Count = 0
for char2 in string2.characters {
if char1 == char2 {
char2Count = char2Count + 1;
}
}
print(char1, char1Count, char2Count)
if char1Count != char2Count {
return false
}
charArray.append(String(char1))
}
}
print(charArray)
return true
}
print(isPermutation("yobabymushaya", of: "mushayaabyboy"))
// Given a string check if its a Permutation of a palindrome or not.
// first it should be a palindrome, then check for permutation.
func isPermutationOfAPalindrome(string : String) -> Bool {
let cnt = string.characters.count
if cnt < 2 {
return false
}
if !isPalindrome(string) {
return false
}
if cnt == 2 {
return false
}
let x = cnt / 2
let arr = Array(string.characters)
for i in 0..<x {
let c1 = arr[i];
let j = cnt - (i+1)
let c2 = arr[j]
if c1 != c2 {
print(c1, c2)
return false
}
}
return true
}
print(isPermutationOfAPalindrome("levle"))
print(isPermutationOfAPalindrome("refer"))
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment