2016-2017 Western Tech Interview Prep Session #1 Questions

longestSubStringWithoutRepeat.java

public class Solution {
    public int lengthOfLongestSubstring(String s) {
        
        if (s.length() == 0 ) {
            return 0;
        }
        
        if (s.length() == 1) {
            return 1;
        }
        
        int count = 0;
        int i = 0;
        
        HashMap<Character,Integer> countMap = new HashMap<Character,Integer>();
        ArrayList<Integer> countList = new ArrayList<Integer>();
        
        while ( i < s.length() ) {
            
            for (int j = i; j < s.length(); j++) {
                if (countMap.containsKey(s.charAt(j)) == false) {
                    count++;
                    countMap.put(s.charAt(j), count);
                } else {
                    countMap.clear();
                    countList.add(count);
                    count = 0;
                    break;
                }
            }
            i++;    
        }
        
        return countLargest(countList);
    }
    
    public int countLargest(ArrayList<Integer> list) {
        int count = 0;
        for (int n = 0; n < list.size(); n++) {
            int arrNum = list.get(n);
            if (arrNum > count) {
                count = arrNum;
            }
        }
        return count;
    }
}

mergeSortedArr.java

public class Solution {
    public void merge(int[] nums1, int m, int[] nums2, int n) {
    
        if (n != 0 || m != 0) {
            for (int i = 0; i < n; i++) {
                nums1[m+i] = nums2[i];
            }
    
            Arrays.sort(nums1);
        }
    }
    
}

validPalindrome.java

public class Solution {
    public boolean isPalindrome(String s) {
        
        if (s.length() == 0) {
            return true;
        }
        
        s = s.replaceAll(" ","");
        s = s.replaceAll("[^A-Za-z0-9 ]", "");
        s = s.toLowerCase();
        for (int i = 0; i < s.length()/2; i++) {
            int end = s.length()-1 - i;
            if (s.charAt(i) != s.charAt(end)) {
                System.out.println(s.charAt(i));
                return false;
            }
        }
        return true;
    }
}