# Min Moves to Make String Without 3 Identical Consecutive Letters

## Description:

2 min readMay 29, 2020

## Solution:

To solve this task we need to find sequences of the same letters and if the sequence is longer than 3 divide length of this sequence to 3 and add result of the division to counters of needed moves.

Example of work:

3 consecutive: baaab, replace the middle a (3 / 3 == 1)

4 consecutive: baaaab, replace the third a (4 / 3 == 1)

5 consecutive: baaaaab, replace the third a (5 / 3 == 1)6 consecutive: baaaaaab -> baabaaab -> baaab -> bab with 2 replacements (6 / 3 == 2)10 consecutive: baaaaaaaaaab -> baabaaaaaaab -> baaaaaaab -> baaaab -> baab with 3 replacements (10 / 3 == 3)

Therefore, we can see the rule: counter += (consecutive char number) / 3

In C++ it will looks like:

int solution(const string & s) {

int res = 0, s_size = s.size(); for(int i = 0; i < s_size;) {

int next = i + 1; // if we meet sequence of the same letters

// scan the string to find length of this sequence

while( (next < s_size) && (s[i] == s[next]) ) { next++; } // Here "next - i" is length of the sequence

// Each third letter should be changed to remove

// too long sequences

res += (next - i) / 3;

i = next; // skip processed letters

}

return res;

}

Repository with the full project you can find here.

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