🥛迭代
类似与归并排序的合并函数，实际还要更简单一些，没有长度的限制
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| class Solution {
public:
ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
ListNode nd(0), *pre = &nd;
while(l1 || l2) {
if(!l1) {
pre->next = l2;
l2 = l2->next;
} else if(!l2) {
pre->next = l1;
l1 = l1->next;
} else if(l1->val < l2->val) {
pre->next = l1;
l1 = l1->next;
} else {
pre->next = l2;
l2 = l2->next;
}
pre = pre->next;
}
return nd.next;
}
};
|
Accepted
208/208 cases passed (8 ms)
Your runtime beats 93.28 % of cpp submissions
Your memory usage beats 76.07 % of cpp submissions (9 MB)
🥛递归
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| class Solution {
public:
ListNode* mergeTwoLists(ListNode* l1, ListNode* l2) {
if(!l1)
return l2;
else if(!l2)
return l1;
else if(l2->val < l1->val) {
l2->next = mergeTwoLists(l2->next, l1);
return l2;
} else {
l1->next = mergeTwoLists(l1->next, l2);
return l1;
}
}
};
|
Accepted
208/208 cases passed (8 ms)
Your runtime beats 93.28 % of cpp submissions
Your memory usage beats 75.58 % of cpp submissions (9 MB)
