重複單鏈表

Question

[3，5，4，2，1]我需要刪除靠近尾部的節點，它應該像[1,2,3,5,4]有什麼建議？

public void delete() { 
    for(Node<T> current = getHead(); current != null; current = current.getNext()){ 

       System.out.println(temp.getValue()); 
       removeValue(temp.getValue()); 
      } 
     } 
    } 
} 

Answer 1

你並不需要刪除所有東西（我的意思是不是通過調用removeValue）。只需將您遇到的值存儲在一個集合中，並且如果該值已經在集合中，則重新鏈接您的列表。如果您沒有使用庫代碼的權利，請使用二叉搜索樹實現您的集合，這將非常簡單且非常高效。

這是我會怎麼做，假設我有Set實現：

public void makeUnique() { 
    Set<T> set  = new MySet<>(); 
    Node<T> current = getHead(); 
    Node<T> previous = null; 
    while (current != null) { 
     // if current.getValue() is already in the set, we skip this node 
     // (the add method of a set returns true iff the element was not 
     // already in the set and if not, adds it to the set) 
     if (set.add(current.getValue()) { 
      // previous represents the last node that was actually inserted in the set. 
      // All duplicate values encountered since then have been ignored so 
      // previous.setNext(current) re-links the list, removing those duplicates 
      if (previous != null) { 
       previous.setNext(current); 
       current.setPrevious(previous); 
      } 
      previous = current; 
     } 
     current = current.getNext(); 
    } 
}