链表

Author: wb-hjk570755

src/com/blankj/myself/GetIntersectionNode_two_linklist.java

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+package com.blankj.myself;
+
+import com.blankj.myself.HasCycle_fast_slow_point.ListNode;
+
+/**
+ * Description:leecode 160. 相交链表
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class GetIntersectionNode_two_linklist {
+    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
+        ListNode pA = headA;
+        ListNode pB = headB;
+        while (pA!=pB){
+            pA = pA==null?headB:pA.next;
+            pB = pB==null?headA:pB.next;
+        }
+        return pA;
+    }
+}

src/com/blankj/myself/HasCycle_fast_slow_point.java

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+package com.blankj.myself;
+
+import java.util.HashSet;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class HasCycle_fast_slow_point {
+
+    public boolean hasCycle(ListNode head) {
+        if(head==null||head.next==null){
+            return false;
+        }
+        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;
+    }
+
+    class ListNode {
+      int val;
+      ListNode next;
+      ListNode(int x) {
+          val = x;
+          next = null;
+      }
+    }
+}

src/com/blankj/myself/HasCycle_hash.java

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+package com.blankj.myself;
+
+import java.util.HashSet;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/2
+ */
+public class HasCycle_hash {
+
+    public boolean hasCycle(ListNode head) {
+        HashSet<ListNode> hashSet = new HashSet<>();
+        while (head!=null){
+            if(hashSet.contains(head)){
+                return true;
+            }else {
+                hashSet.add(head);
+                head = head.next;
+            }
+        }
+        return false;
+    }
+
+    class ListNode {
+      int val;
+      ListNode next;
+      ListNode(int x) {
+          val = x;
+          next = null;
+      }
+    }
+}

src/com/blankj/myself/PredictTheWinner_Dp.java

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+package com.blankj.myself;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/1
+ */
+public class PredictTheWinner_Dp {
+    public static void main(String[] args) {
+        int v[] = { 1, 2, 3, 6, 9, 5, 7, 4, 2, 6, 9, 5, 8, 7, 2, 1, 55, 3, 6, 9, 7, 5, 2 };
+        PredictTheWinner_Dp predictTheWinner = new PredictTheWinner_Dp();
+        System.out.println(predictTheWinner.PredictTheWinner(v));
+    }
+
+    public boolean PredictTheWinner(int[] nums) {
+        if(nums.length%2==0){
+            return true;
+        }
+
+        int[][] dp = new int[nums.length][nums.length];
+        for(int i=0;i<nums.length;i++){
+            dp[i][i] = nums[i];
+        }
+
+        for(int i=nums.length-2;i>=0;i--){
+            for (int j=i+1;j<nums.length;j++){
+                dp[i][j] = Math.max(nums[i]-dp[i+1][j],nums[j]-dp[i][j-1]);
+            }
+        }
+        return dp[0][nums.length-1]>=0;
+    }
+
+
+}

src/com/blankj/myself/StrStr.java

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+package com.blankj.myself;
+
+import java.util.Objects;
+
+/**
+ * Description:
+ * Copyright: Copyright (c) 2012
+ * Company: keruyun Technology(Beijing) Chengdu Co. Ltd.
+ *
+ * @author huangjk
+ * @version 1.0 2020/10/1
+ */
+public class StrStr {
+    public static void main(String[] args) {
+        StrStr strStr = new StrStr();
+        strStr.strStr("mississippi",
+            "issip");
+    }
+
+    public int strStr(String haystack, String needle) {
+        int hLen = haystack.length();
+        int nLen = needle.length();
+
+        for (int i=0;i<hLen-nLen;i++){
+            for (int j=0; j<nLen;j++){
+                if (haystack.charAt(i+j)==needle.charAt(j)){
+                    if(j==nLen-1){
+                        return i;
+                    }
+                }else {
+                    break;
+                }
+            }
+
+        }
+        return -1;
+    }
+}