Excel Sheet & Remove Duplicates

Excel Sheet Column Title

public class Solution {
    public String convertToTitle(int n) {
        if (n <= 0) {
            return "";
        }

        StringBuffer sb = new StringBuffer();
        while (--n >= 0) {
            sb.insert(0, (char) (n % 26 + 'A'));
            n /= 26;
        }
        return sb.toString();
    }
}

Excel Sheet Column Number

public class Solution {
    public int titleToNumber(String s) {
        StringBuffer sb = new StringBuffer();
        int sum = 0;
        for (int i = 0; i < s.length(); i++) {
            sum = sum * 26;
            char c = s.charAt(i);
            sum += c - 'A' + 1;
        }
        return sum;
    }
}

Remove Element

public class Solution {
    public int removeElement(int[] nums, int val) {
        int i = 0;
        for (int j = 0; j < nums.length; j++) {
            if (nums[j] != val) {
                nums[i++] = nums[j];
            }
        }
        return i;
    }
}

Move Zeroes

public class Solution {
    public void moveZeroes(int[] nums) {
        int i = 0;
        for (int j = 0; j < nums.length; j++) {
            if (nums[j] != 0) {
                nums[i++] = nums[j];
            }
        }
        for (int j = i; j < nums.length; j++) {
            nums[j] = 0;
        }
    }
}

Remove Duplicates from Sorted Array

public class Solution {
    public int removeDuplicates(int[] nums) {
        int i = 0;
        for (int j = 1; j < nums.length; j++) {
            if (nums[j] != nums[i]) {
                nums[++i] = nums[j];
            }
        }
        return i + 1;
    }
}

Remove Duplicates from Sorted Array II

public class Solution {
    public int removeDuplicates(int[] nums) {
        int i = 0, count = 1;
        for (int j = 1; j < nums.length; j++) {
            if (nums[j] != nums[i] || count < 2) {
                if (nums[j] == nums[i]) {
                    count++;
                } else {
                    count = 1;
                }
                nums[++i] = nums[j];
            }
        }
        return i + 1;
    }
}