最长快乐字符串

/*
 * 思路：
 * 使用Java Stream API来创建快乐字符串
 * 由于Stream不直接支持对复杂逻辑的动态决策，我们这里提供的实现会比较传统Java版本更加清晰
 */
import java.util.Arrays;
import java.util.stream.Collectors;

public class SolutionStream {
    public String longestDiverseString(int a, int b, int c) {
        StringBuilder result = new StringBuilder();
        int[] count = {a, b, c};
        char[] chars = {'a', 'b', 'c'};

        while (true) {
            int maxIndex = getMaxCountIndex(count);
            if (count[maxIndex] == 0) {
                break;
            }
            int length = result.length();
            if (length >= 2 && result.charAt(length - 1) == chars[maxIndex] && result.charAt(length - 2) == chars[maxIndex]) {
                int secondMaxIndex = getSecondMaxCountIndex(count, maxIndex);
                if (count[secondMaxIndex] == 0) {
                    break;
                }
                result.append(chars[secondMaxIndex]);
                count[secondMaxIndex]--;
            } else {
                result.append(chars[maxIndex]);
                count[maxIndex]--;
            }
        }
        return result.toString();
    }

    private int getMaxCountIndex(int[] count) {
        return Arrays.stream(new int[]{0, 1, 2}).boxed()
                .max((i, j) -> count[i] - count[j])
                .orElse(0);
    }

    private int getSecondMaxCountIndex(int[] count, int excludeIndex) {
        return Arrays.stream(new int[]{0, 1, 2}).boxed()
                .filter(i -> i != excludeIndex)
                .max((i, j) -> count[i] - count[j])
                .orElse(-1);
    }
}