Push Dominoes | Leetcode 838

class Domino {
public:
    void doubleDominoPush(int last_R, int pos, string& dominoes) {
        while (last_R < pos) {
            dominoes[last_R++] = 'R';
            dominoes[pos--] = 'L';
        }
    }
    
    void leftDominoPush(int start, int end, string& dominoes) {
        while (start <= end)
            dominoes[start++] = 'L';
    }
    
    void rightDominoPush(int last_R, int pos, string& dominoes) {
        while (last_R <= pos)
            dominoes[last_R++] = 'R';
    }
};

class Solution {
public:
    string pushDominoes(string dominoes) {
        Domino newDomino;  // Removed 'new' since we're not using pointers
        int last_L = -1, last_R = -1;
        int n = dominoes.size();

        for (int pos = 0; pos < n; pos++) {
            if (dominoes[pos] == 'L') {
                if (last_R > last_L) {
                    newDomino.doubleDominoPush(last_R, pos, dominoes);
                }
                else if ((last_L > last_R) || last_L == -1) {
                    newDomino.leftDominoPush(last_L + 1, pos, dominoes);
                }
                last_L = pos;
            }
            else if (dominoes[pos] == 'R') {
                if (last_R > last_L) {
                    newDomino.rightDominoPush(last_R, pos, dominoes);
                }
                last_R = pos;
            }
        }
        
        // Final case: (R)RR...R(end)
        if (last_R > last_L)
            newDomino.rightDominoPush(last_R, n - 1, dominoes);

        return dominoes;
    }
};
/*
//JAVA
class Domino {
    public void doubleDominoPush(int last_R, int pos, StringBuilder dominoes) {
        while (last_R < pos) {
            dominoes.setCharAt(last_R++, 'R');
            dominoes.setCharAt(pos--, 'L');
        }
    }
    
    public void leftDominoPush(int start, int end, StringBuilder dominoes) {
        while (start <= end) {
            dominoes.setCharAt(start++, 'L');
        }
    }
    
    public void rightDominoPush(int last_R, int pos, StringBuilder dominoes) {
        while (last_R <= pos) {
            dominoes.setCharAt(last_R++, 'R');
        }
    }
}

class Solution {
    public String pushDominoes(String dominoes) {
        Domino newDomino = new Domino();
        int last_L = -1, last_R = -1;
        int n = dominoes.length();
        StringBuilder sb = new StringBuilder(dominoes);

        for (int pos = 0; pos < n; pos++) {
            if (sb.charAt(pos) == 'L') {
                if (last_R > last_L) {
                    newDomino.doubleDominoPush(last_R, pos, sb);
                }
                else if ((last_L > last_R) || last_L == -1) {
                    newDomino.leftDominoPush(last_L + 1, pos, sb);
                }
                last_L = pos;
            }
            else if (sb.charAt(pos) == 'R') {
                if (last_R > last_L) {
                    newDomino.rightDominoPush(last_R, pos, sb);
                }
                last_R = pos;
            }
        }
        
        // Final case: (R)RR...R(end)
        if (last_R > last_L) {
            newDomino.rightDominoPush(last_R, n - 1, sb);
        }

        return sb.toString();
    }
}

#Python
class Domino:
    def doubleDominoPush(self, last_R, pos, dominoes):
        dominoes_list = list(dominoes)
        while last_R < pos:
            dominoes_list[last_R] = 'R'
            dominoes_list[pos] = 'L'
            last_R += 1
            pos -= 1
        return ''.join(dominoes_list)
    
    def leftDominoPush(self, start, end, dominoes):
        dominoes_list = list(dominoes)
        while start <= end:
            dominoes_list[start] = 'L'
            start += 1
        return ''.join(dominoes_list)
    
    def rightDominoPush(self, last_R, pos, dominoes):
        dominoes_list = list(dominoes)
        while last_R <= pos:
            dominoes_list[last_R] = 'R'
            last_R += 1
        return ''.join(dominoes_list)

class Solution:
    def pushDominoes(self, dominoes: str) -> str:
        newDomino = Domino()
        last_L = -1
        last_R = -1
        n = len(dominoes)
        result = dominoes

        for pos in range(n):
            if result[pos] == 'L':
                if last_R > last_L:
                    result = newDomino.doubleDominoPush(last_R, pos, result)
                elif (last_L > last_R) or (last_L == -1):
                    result = newDomino.leftDominoPush(last_L + 1, pos, result)
                last_L = pos
            elif result[pos] == 'R':
                if last_R > last_L:
                    result = newDomino.rightDominoPush(last_R, pos, result)
                last_R = pos
        
        # Final case: (R)RR...R(end)
        if last_R > last_L:
            result = newDomino.rightDominoPush(last_R, n - 1, result)

        return result
*/