fd

Author: dingjikerbo

README.md

@@ -16,6 +16,7 @@
  - [Facebook面试总结](https://github.com/dingjikerbo/leetcode/blob/master/doc/Facebook.md)
  - [Bitset技巧](https://github.com/dingjikerbo/leetcode/blob/master/doc/BitSet.md)
  - [Map新接口](https://github.com/dingjikerbo/leetcode/blob/master/doc/Map.md)
+ - [其它题目](extras.md)
 
 <br/><br/>
 

extras.md

@@ -0,0 +1,4 @@
+# 其它题目
+
+### Google
+ - [Remove consecutive node from single list](leetcode/src/RemoveDuplicateList.java)

leetcode/solution/src/BinaryTreePostorderTraversal.java

@@ -35,10 +35,11 @@ public List<Integer> postorderTraversal2(TreeNode root) {
             } else {
                 TreeNode peek = stack.peek();
                 if (peek.right != null && last != peek.right) {
-                    root = peek.right;
+                    root = peek.right; // 只有这里要设置root
                 } else {
                     result.add(peek.val);
                     last = stack.pop();
+                    // 此时root仍为null
                 }
             }
         }

leetcode/solution/src/ContainsDuplicateIII.java

@@ -10,8 +10,7 @@ public class ContainsDuplicateIII {
     /**
      * 这题要注意溢出问题，干脆都用long
      * 时间复杂度O(nlg(min(n,k))
-     * for循环走到当前的nums[i]说明之前的都不行，因此只要判断当前
-     * nums[i]的加入是否可以即可，因此只要判断nums[i]相邻的上下两个数是否在t范围内
+     * 这里相当于维护了一个window，每次新遍历到一个数，都查看上下相邻的数是否满足条件
      */
     public boolean containsNearbyAlmostDuplicate(int[] nums, int k, int t) {
         TreeSet<Long> set = new TreeSet<>();

leetcode/solution/src/MaximumGap.java

@@ -53,6 +53,7 @@ public int maximumGap(int[] nums) {
             maxGap = Math.max(maxGap, mins[i] - last);
             last = maxs[i];
         }
+        // 最后的max别忘了
         maxGap = Math.max(maxGap, max - last);
         return maxGap;
     }

leetcode/solution/src/RemoveDuplicateList.java

@@ -0,0 +1,35 @@
+public class RemoveDuplicateList {
+
+    /**
+     * 一个链表，删除相邻且重复的
+     * 如 1, 3, 3, 3, 1, 2, 4, 4，只保留1, 1, 2
+     */
+    public ListNode removeDup(ListNode head) {
+        ListNode dummy = new ListNode(0), cur = dummy;
+
+        ListNode node = null;
+        int count = 0;
+
+        for (ListNode p = head; p != null; p = p.next) {
+            if (node == null || node.val == p.val) {
+                node = p;
+                count++;
+            } else {
+                if (count == 1) {
+                    cur.next = node;
+                    cur = cur.next;
+                }
+                node = p;
+                count = 1;
+            }
+        }
+
+        if (node != null && count == 1) {
+            cur.next = node;
+            cur = cur.next;
+        }
+
+        cur.next = null;
+        return dummy.next;
+    }
+}

leetcode/src/Main.java

@@ -1,22 +1,58 @@
-import com.sun.org.apache.xpath.internal.operations.Bool;
-
-import java.util.*;
-import java.util.concurrent.*;
 
 public class Main {
 
     public static class Solution {
 
-        public int myAtoi(String str) {
-            str = str.trim();
-            if (str.length() == 0) {
-                return
+        ListNode removeDup(ListNode head) {
+            ListNode dummy = new ListNode(0), cur = dummy;
+
+            ListNode node = null;
+            int count = 0;
+
+            for (ListNode p = head; p != null; p = p.next) {
+                if (node == null || node.val == p.val) {
+                    node = p;
+                    count++;
+                } else {
+                    if (count == 1) {
+                        cur.next = node;
+                        cur = cur.next;
+                    }
+                    node = p;
+                    count = 1;
+                }
             }
+
+            if (node != null && count == 1) {
+                cur.next = node;
+                cur = cur.next;
+            }
+
+            cur.next = null;
+            return dummy.next;
         }
 
+        ListNode make(int[] arr) {
+            ListNode dummy = new ListNode(0), cur = dummy;
+            for (int n : arr) {
+                cur.next = new ListNode(n);
+                cur = cur.next;
+            }
+            return dummy.next;
+        }
+
+    }
 
 
     public static void main(String[] args) {
         Solution s = new Solution();
+        int[] arr = {
+                1, 3, 3, 3, 1, 2, 4, 4, 1
+        };
+        ListNode head = s.make(arr);
+        head = s.removeDup(head);
+        for (ListNode p = head; p != null; p = p.next) {
+            System.out.print(p.val + " ");
+        }
     }
 }