根據給定標准（遞歸）計算二叉樹中的節點

Question

我想使用 java 中的二叉搜索樹遞歸計算成績低於 60 的失敗學生的數量。 我不知道我的方法是否正確。 之后找到要在公共包裝方法中使用的輔助方法

    private int NumberfailStudents(int numoffailed, BNode current) {
        // BaseCase
        if (current == null) {

            return 0 + numofpassed;

        } else {

            if (current.data.getGrades() < 60) {
                return ++numoffailed;
            }

            if (current.left != null) {
                return NumberfailStudents(numoffailed, current.left);
            }
            if (current.right != null) {
                return NumberfailStudents(numoffailed, current.right);
            }

        }

        return numoffailed;

    }

Answer 1

如果檢查電流的 if 條件是 null 應該返回numoffailed而不是numofpassed

我已更新NumberFailStudents以匹配命名約定

    private int NumberFailStudents(int numOfFailed, BNode current) {
        if (current == null)
            return numOfFailed;

        if (current.data.getGrades() < 60)
            ++numOfFailed;

        if (current.left != null)
            numOfFailed = NumberFailStudents(numOfFailed, current.left);

        if (current.right != null)
            numOfFailed = NumberFailStudents(numOfFailed, current.right);

        return numOfFailed;
    }