添加RBTree实现

Author: MistRay

leetcode/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>algorithm-study</artifactId>
+        <groupId>com.mistray</groupId>
+        <version>1.0-SNAPSHOT</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>leetcode</artifactId>
+
+
+</project>

leetcode/src/main/java/com/mistray/array/HowManyNumbersAreSmallerThanTheCurrentNumber1365.java

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+package com.mistray.array;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * @author ZJY(MistRay)
+ * @Project algorithm-study
+ * @Package com.mistray.array
+ * @create 2020年03月02日 17:39
+ * @Desc
+ */
+public class HowManyNumbersAreSmallerThanTheCurrentNumber1365 {
+
+    public static void main(String[] args) {
+        int[] nums = {8, 1, 2, 2, 3};
+        int[] ints = smallerNumbersThanCurrent(nums);
+        for (int i = 0; i < ints.length; i++) {
+            System.out.println(ints[i]);
+
+        }
+    }
+
+    public static int[] smallerNumbersThanCurrent(int[] nums) {
+        int length = nums.length;
+        int[] temp = new int[length];
+        // 复制并排序
+        System.arraycopy(nums, 0, temp, 0, length);
+        Arrays.sort(temp);
+        Map<Integer, Integer> map = new HashMap<>();
+        // temp是有序的
+        for (int i = 0, num = 0, t = temp[0]; i < temp.length; i++) {
+            // t用来临时存储temp中相邻的重复数据
+            if (temp[i] == t) {
+                // 如果map中不包含temp[i]
+                if (!map.containsKey(temp[i])) {
+                    // 将该元素插入到map中.
+                    map.put(temp[i], 0);
+                }
+            } else {
+                map.put(temp[i], num);
+                t = temp[i];
+            }
+            num++;
+        }
+        int[] res = new int[length];
+        for (int i = 0; i < nums.length; i++) {
+            res[i] = map.get(nums[i]);
+        }
+        return res;
+    }
+}

leetcode/src/main/java/com/mistray/link/AddTwoNumbers2.java

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+package com.mistray.link;
+
+/**
+ * @author ZJY(MistRay)
+ * @Project algorithm-study
+ * @Package com.mistray.link
+ * @create 2020年03月02日 15:50
+ * @Desc
+ */
+public class AddTwoNumbers2 {
+
+    public static void main(String[] args) {
+        ListNode node = new ListNode(5);
+        node.next = new ListNode(5);
+        node.next.next = new ListNode(5);
+
+        ListNode node2 = new ListNode(6);
+        node2.next = new ListNode(7);
+        node2.next.next = new ListNode(6);
+
+
+        addTwoNumbers(node,node2);
+    }
+
+    /**
+     * 输入：(2 -> 4 -> 3) + (5 -> 6 -> 4)
+     * 输出：7 -> 0 -> 8
+     * 输入：(5 -> 5 -> 3) + (6 -> 7 -> 2)
+     * 输出：6 -> 3 -> 1
+     * 原因：342 + 465 = 807
+     *
+     * @param l1
+     * @param l2
+     * @return
+     */
+    public static ListNode addTwoNumbers(ListNode l1, ListNode l2) {
+        ListNode pre = new ListNode(0);
+        ListNode cur = pre;
+        int carry = 0;
+        while(l1 != null || l2 != null) {
+            int x = l1 == null ? 0 : l1.val;
+            int y = l2 == null ? 0 : l2.val;
+            int sum = x + y + carry;
+
+            carry = sum / 10;
+            sum = sum % 10;
+            cur.next = new ListNode(sum);
+
+            cur = cur.next;
+            if(l1 != null) {
+                l1 = l1.next;
+            }
+            if(l2 != null) {
+                l2 = l2.next;
+            }
+        }
+        if(carry == 1) {
+            cur.next = new ListNode(carry);
+        }
+        return pre.next;
+    }
+
+}

leetcode/src/main/java/com/mistray/link/IntersectionOfTwoLinkedLists160.java

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+package com.mistray.link;
+
+/**
+ * @author ZJY(MistRay)
+ * @Project algorithm-study
+ * @Package com.mistray.link
+ * @create 2020年03月03日 15:48
+ * @Desc
+ */
+public class IntersectionOfTwoLinkedLists160 {
+
+    public static void main(String[] args) {
+
+    }
+
+    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
+        ListNode a = headA;
+        ListNode b = headB;
+        while (a != b) {
+            a = a.next;
+            if (a == null) {
+                a = headB;
+            }
+            b = b.next;
+            if (b == null) {
+                b = headA;
+            }
+        }
+        return a;
+    }
+}

leetcode/src/main/java/com/mistray/link/LinkedListCycle141.java

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+package com.mistray.link;
+
+import java.util.List;
+
+/**
+ * @author ZJY(MistRay)
+ * @Project algorithm-study
+ * @Package com.mistray.link
+ * @create 2020年03月03日 14:18
+ * @Desc
+ */
+public class LinkedListCycle141 {
+
+    public static void main(String[] args) {
+
+    }
+
+    public boolean hasCycle(ListNode head) {
+        ListNode fast = head;
+        ListNode slow = head;
+        while (fast != null && fast.next != null) {
+            fast = fast.next.next;
+            slow = slow.next;
+            if (fast == slow) {
+                return true;
+            }
+        }
+        return false;
+    }
+}

leetcode/src/main/java/com/mistray/link/LinkedListCycleii142.java

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+package com.mistray.link;
+
+/**
+ * @author ZJY(MistRay)
+ * @Project algorithm-study
+ * @Package com.mistray.link
+ * @create 2020年03月03日 16:23
+ * @Desc
+ */
+public class LinkedListCycleii142 {
+    public static void main(String[] args) {
+
+    }
+
+    public ListNode detectCycle(ListNode head) {
+        ListNode slow = head, fast = head;
+        while (fast.next != null && fast.next.next != null) {
+            slow = slow.next;
+            fast = fast.next.next;
+            if (slow == fast) {
+                break;
+            }
+        }
+        if (fast.next == null || fast.next.next == null) {
+            return null;
+        }
+
+        slow = head;
+        while (slow != fast) {
+            slow = slow.next;
+            fast = fast.next;
+        }
+        return slow;
+    }
+}

leetcode/src/main/java/com/mistray/link/ListNode.java

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+package com.mistray.link;
+
+public class ListNode {
+        int val;
+        ListNode next;
+
+        ListNode(int x) {
+            val = x;
+        }
+    }

leetcode/src/main/java/com/mistray/link/MergeTwoSortedLists21.java

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+package com.mistray.link;
+
+/**
+ * @author ZJY(MistRay)
+ * @Project algorithm-study
+ * @Package com.mistray.link
+ * @create 2020年03月02日 11:41
+ * @Desc
+ */
+public class MergeTwoSortedLists21 {
+
+
+    public static void main(String[] args) {
+
+    }
+
+    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
+        // 当l1为空,返回l2
+        if (l1 == null) {
+            return l2;
+        }
+
+        // 当l2位空,返回l1
+        if (l2 == null) {
+            return l1;
+        }
+
+        // 当l1的值小于l2时
+        if (l1.val < l2.val) {
+            l1.next = mergeTwoLists(l1.next, l2);
+            return l1;
+        } else {
+            l2.next = mergeTwoLists(l2.next, l2);
+            return l2;
+        }
+
+    }
+
+
+}

leetcode/src/main/java/com/mistray/link/ReverseLinkedList206.java

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+package com.mistray.link;
+
+/**
+ * @author ZJY(MistRay)
+ * @Project algorithm-study
+ * @Package com.mistray.link
+ * @create 2020年03月02日 10:57
+ * @Desc
+ */
+public class ReverseLinkedList206 {
+
+
+    public static void main(String[] args) {
+    }
+
+
+    public static ListNode reverseList(ListNode head) {
+        // 上一个节点
+        ListNode pre = null;
+        // 当前节点
+        ListNode cur = head;
+        // 承载下一个节点的临时节点
+        ListNode tmp = null;
+
+        while (cur != null) {
+            // 将当前节点cur的下一个节点赋给临时节点tmp
+            tmp = cur.next;
+            // 将上一个节点赋给当前节点的下一个节点
+            cur.next = pre;
+            // 将pre和cur后移一位
+            pre = cur;
+            cur = tmp;
+        }
+        return pre;
+    }
+
+
+}