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by Sumit Chourasia | Oct 02, 2020 | Category :coding | Tags : algorithm data-structure easy leetcode string

Thousand Separator - String - Easy - LeetCode

Thousand Separator - String - Easy - LeetCode

Given an integer n, add a dot (".") as the thousands separator and return it in string format.

 

Example 1:

Input: n = 987
Output: "987"
Example 2:

Input: n = 1234
Output: "1.234"
Example 3:

Input: n = 123456789
Output: "123.456.789"
Example 4:

Input: n = 0
Output: "0"
 

Constraints:

0 <= n < 2^31

public class Solution {
    public string ThousandSeparator(int n) {
        if(n==0){
            return "0";
        }
        var stack = new Stack<char>();
        int i=0;
        while(n>0){
            stack.Push((char)((n%10)+48));
            n/=10;
            i++;
            if(i%3==0 && n!=0){
                stack.Push('.');
            }
        }
        
        var sb = new StringBuilder();
        while(stack.Count>0){
            sb.Append(stack.Pop());
        }
        
        return sb.ToString();
    }
}

Time Complexity: O(n)

Space Complexity: O(n)

Contributed By: Sumit Chourasia
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