java - Java中不使用队列的二叉树右 View

Question

HERE是不使用队列的二叉树右 View 的c++实现。当我尝试将它转换为 Java 时，它不起作用。这是我的 Java 代码:

(我认为很可能是因为我没有正确理解算法和处理 maxLevel 指针/引用)

public static void rightView(TreeNode tNode){
    int maxLevel = 0;
    rViewUtil(tNode, 1,maxLevel);
}

public static void rViewUtil(TreeNode tNode, int level, int maxLevel){
    if(tNode==null)
        return;
    if(maxLevel < level){
        System.out.print(tNode.value + " ");
        maxLevel = level;
    }
    rViewUtil(tNode.right, level+1, maxLevel);
    rViewUtil(tNode.left, level+1, maxLevel);
}

Answer 1

本着@lifus 回答的精神，但避免可变状态，您可以使用函数 return 来设置 maxLevel

public static void rightView(TreeNode tNode){
    int maxLevel = 0;
    rViewUtil(tNode, 1,maxLevel);
}

public static int rViewUtil(TreeNode tNode, int level, int maxLevel){
    if(tNode==null)
        return;
    if(maxLevel < level){
        System.out.print(tNode.value + " ");
        maxLevel = level;
    }
    maxLevel = rViewUtil(tNode.right, level+1, maxLevel);
    maxLevel = rViewUtil(tNode.left, level+1, maxLevel);
    return maxLevel
}