Merge branch 'main' of https://github.com/stoychoX/Data-structures-and-algorithms

4 files changed, 103 insertions, 0 deletions

diff --git a/Practicum/pract05/solutions/Task01.cpp b/Practicum/pract05/solutions/Task01.cpp
new file mode 100644
index 0000000..1f9e7a9
--- /dev/null
+++ b/Practicum/pract05/solutions/Task01.cpp
@@ -0,0 +1,17 @@
+SinglyLinkedListNode* reverse(SinglyLinkedListNode* llist) {
+    if(!llist)
+        return nullptr;
+        
+    SinglyLinkedListNode* curr = llist;
+    SinglyLinkedListNode* prev = nullptr;
+    
+    while(curr)
+    {
+        SinglyLinkedListNode* next = curr->next;
+        curr->next = prev;
+        prev = curr;
+        curr = next;
+    }
+    
+    return prev;
+}
diff --git a/Practicum/pract05/solutions/Task02.cpp b/Practicum/pract05/solutions/Task02.cpp
new file mode 100644
index 0000000..4905d58
--- /dev/null
+++ b/Practicum/pract05/solutions/Task02.cpp
@@ -0,0 +1,16 @@
+class Solution {
+public:
+    ListNode* middleNode(ListNode* head) {
+        if(!head)
+            return nullptr;
+      
+        ListNode* middle = head;
+        ListNode* end = head;
+
+        while(end != nullptr && end->next != nullptr) {
+            middle = middle->next;
+            end = end->next->next;
+        }
+        return middle;        
+    }
+};
diff --git a/Practicum/pract05/solutions/Task03.cpp b/Practicum/pract05/solutions/Task03.cpp
new file mode 100644
index 0000000..42282c6
--- /dev/null
+++ b/Practicum/pract05/solutions/Task03.cpp
@@ -0,0 +1,18 @@
+bool has_cycle(SinglyLinkedListNode* head) {
+    if(!head)
+        return false;
+        
+    SinglyLinkedListNode* slow = head;
+    SinglyLinkedListNode* fast = head;
+    
+    while(fast && fast->next)
+    {
+        slow = slow->next;
+        fast = fast->next->next;
+        
+        if(slow == fast)
+            return true;
+    }
+    
+    return false;
+}
diff --git a/Practicum/pract05/solutions/Task04.cpp b/Practicum/pract05/solutions/Task04.cpp
new file mode 100644
index 0000000..3fc11a5
--- /dev/null
+++ b/Practicum/pract05/solutions/Task04.cpp
@@ -0,0 +1,52 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    size_t getLen(ListNode* head)
+    {
+        size_t cnt = 0;
+        while(head)
+        {
+            head = head->next;
+            cnt++;
+        }
+
+        return cnt;
+    }
+    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
+        if(!headA || !headB)
+            return nullptr;
+
+        size_t sizeA = getLen(headA);
+        size_t sizeB = getLen(headB);
+
+        while(sizeA > sizeB)
+        {
+            headA = headA->next;
+            sizeA--;
+        }
+
+        while(sizeB > sizeA)
+        {
+            headB = headB->next;
+            sizeB--;
+        }
+
+        while(headA && headB)
+        {
+            if(headA == headB)
+                return headA;
+
+            headA = headA->next;
+            headB = headB->next;
+        }
+        
+        return nullptr;
+    }
+};