leetcode

LeetCode 75 II: Day 4

2 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/ Problems/0148.cpp b/ Problems/0148.cpp

@@ -0,0 +1,38 @@

class Solution {

public:

ListNode *sortList(ListNode *head) {

if (!head || !head->next) return head;

ListNode *mid = getMid(head), *left = sortList(head),

*right = sortList(mid);

return merge(left, right);

}

ListNode *merge(ListNode *list1, ListNode *list2) {

ListNode head, *t = &head;

while (list1 && list2) {

if (list1->val < list2->val) {

t = t->next = list1;

list1 = list1->next;

} else {

t = t->next = list2;

list2 = list2->next;

}

}

t->next = list1 ? list1 : list2;

return head.next;

}

ListNode *getMid(ListNode *head) {

ListNode *fast, *slow;

fast = slow = head;

while (fast->next && fast->next->next) {

fast = fast->next->next;

slow = slow->next;

}

fast = slow->next;

slow->next = nullptr;

return fast;

}

};

diff --git a/ README.md b/ README.md

@@ -114,6 +114,7 @@ for solving problems. | 0143 | Medium | [Reorder List](Problems/0143.cpp) | | 0144 | Medium | [Binary Tree Preorder Traversal](Problems/0144.cpp) | | 0145 | Easy | [Binary Tree Postorder Traversal](Problems/0145.cpp) |

| 0148 | Medium | [Sort List](Problems/0148.cpp) |

| 0149 | Hard | [Max Points on a Line](Problems/0149.cpp) | | 0150 | Medium | [Evaluate Reverse Polish Notation](Problems/0150.cpp) | | 0151 | Medium | [Reverse Words in a String](Problems/0151.cpp) |