feature ：打卡删除链表

andycom · andycom · commit a41ced76af8a · 2021-03-26T10:07:02.000+08:00
diff --git a/src/main/java/com/fancv/leetCode/LinkedList/deleteDuplicatesOne.java b/src/main/java/com/fancv/leetCode/LinkedList/deleteDuplicatesOne.java
@@ -0,0 +1,39 @@
+package com.fancv.leetCode.LinkedList;
+
+public class deleteDuplicatesOne {
+
+    public static void main(String[] args) {
+        ListNode a = new ListNode(4, null);
+        ListNode b = new ListNode(2, a);
+        ListNode c = new ListNode(2, b);
+        ListNode d = new ListNode(2, c);
+        ListNode e = new ListNode(1, d);
+
+        ListNode result = deleteDuplicates(e);
+        System.out.println(result.val);
+    }
+
+
+    /**
+     * 删除链表中重复元素  回调
+     * 1 1 2 3 3
+     *
+     * @param head
+     * @return
+     */
+    public static ListNode deleteDuplicates(ListNode head) {
+        if (head == null || head.next == null) {
+            return head;
+        }
+        ListNode sail = head.next;
+        if (head.val == sail.val) {
+            while (sail != null && head.val == sail.val) {
+                sail = sail.next;
+            }
+        }
+        head.next = deleteDuplicates(sail);
+
+        return head;
+    }
+
+}
diff --git a/src/main/java/com/fancv/leetCode/mathematics/MathArray.java b/src/main/java/com/fancv/leetCode/mathematics/MathArray.java
@@ -0,0 +1,27 @@
+package com.fancv.leetCode.mathematics;
+
+import java.util.Arrays;
+
+/**
+ * @author hamish-wu
+ */
+public class MathArray {
+
+
+    public static void main(String[] args) {
+
+    }
+
+    public int maximumGap(int[] nums) {
+
+        //1.排序
+        Arrays.sort(nums);
+
+        //2.遍历元素，计算相邻元素差值 最大
+
+
+
+        return 0;
+    }
+
+}
diff --git a/src/main/java/com/fancv/leetCode/mathematics/MyMathematics.java b/src/main/java/com/fancv/leetCode/mathematics/MyMathematics.java
@@ -6,10 +6,11 @@
 public class MyMathematics {
 
     public static void main(String[] args) {
-        System.out.println(isUgly(0));
-        System.out.println(isUgly(2));
-        System.out.println(isUgly(1024));
-        System.out.println(isUgly(14));
+        System.out.println(nthUglyNumber(400));
+        System.out.println(nthUglyNumber(800));
+        System.out.println(nthUglyNumber(1200));
+        System.out.println(nthUglyNumber(1600));
+        System.out.println(nthUglyNumber(200));
     }
 
     public static int[] findErrorNums(int[] nums) {
@@ -63,7 +64,7 @@ public static boolean threeConsecutiveOdds(int[] arr) {
      */
     public static boolean isUgly(int n) {
         boolean r = false;
-        if(n==0){
+        if (n == 0) {
             return r;
         }
         //1.偶数
@@ -97,6 +98,82 @@ else if (n % 3 == 0) {
             r = true;
         }
         return r;
+    }
+
+    /**
+     * 丑数，数字 2 3 5 乘积
+     *
+     * @param n
+     * @return
+     */
+    public boolean isUgly2(int n) {
+        boolean r = false;
+        //1.偶数
+        while (n % 2 == 0) {
+            n = n / 2;
+        }
+        //2.奇数 3的倍数
+        while (n % 3 == 0) {
+            n = n / 3;
+        }
+        while (n % 5 == 0) {
+            n = n / 5;
+        }
+        if (n == 1) {
+            r = true;
+        }
+        return r;
+    }
+
+    /**
+     * 第N 个丑数 笨办法
+     *
+     * @param n
+     * @return
+     */
+    public static int nthUglyNumber(int n) {
+        int i = 1;
+        int temp = 0;
+        if (n > 200) {
+            i = 16200;
+            temp = 199;
+        } else if (n > 400) {
+            i = 311040;
+            temp = 399;
+        } else if (n > 800) {
+            i = 12754584;
+            temp = 799;
+        } else if (n > 1200) {
+            i = 174960000;
+            temp = 799;
+        } else if (n > 1600) {
+            i = 1399680000;
+            temp = 1599;
+        }
+        for (; i < Integer.MAX_VALUE; i++) {
+            if (isUgly(i)) {
+                temp++;
+            }
+            if (temp == n) {
+                return i;
+            }
+        }
+        return 0;
+    }
+
+    /**
+     * 第N 个丑数  三指针算法
+     *
+     * @param n
+     * @return
+     */
+    public static int nthUglyNumber2(int n) {
+
+
+
+
+
 
+        return 0;
     }
 }
