Delete Characters to Make Fancy String

Leetcode Problem:

• Delete Characters to Make Fancy String

Summary

• The problem is to delete the minimum possible number of characters from a string to make it a fancy string, where no three consecutive characters are equal.

Approach

• The approach used is to iterate through the string and check for consecutive characters
• If three consecutive characters are equal, they are skipped
• Otherwise, they are added to the result string.

Complexity

• O(n), where n is the length of the string

Explanation

• The solution code initializes a string `ss` with the first character of the input string
• It then iterates through the rest of the string, checking for consecutive characters
• If three consecutive characters are equal, they are skipped
• Otherwise, they are added to the result string
• The code also keeps track of the count of consecutive characters and resets it when a different character is encountered.

Solution Code:

class Solution {
public:
    string makeFancyString(string s) {
        string ss = string(1,s[0]);
        int repeat_cnt = 1;
        char before_char = s[0];
        for(int i = 1 ;  i < s.size(); i++){
            if (before_char == s[i]){
                repeat_cnt++;
                if(repeat_cnt >= 3) continue;
            } else {
                repeat_cnt = 1;
            }
            ss += s[i];
            before_char = s[i];
        }
        return ss;
    }
};