[leetcode]Insertion Sort List

class Solution {
public:
ListNode *insertionSortList(ListNode *head) {
ListNode *o_dummy = new ListNode(0);
ListNode *n_dummy = new ListNode(0);
o_dummy->next = head;
ListNode *last = n_dummy;
while (o_dummy->next != NULL) {
ListNode *prev = o_dummy;
ListNode *node = prev->next;
// find node with min val
ListNode *min_node = node;
ListNode *prev_node = prev;
while (node != NULL) {
if (node->val < min_node->val) {
min_node = node;
prev_node = prev;
}
node = node->next;
prev = prev->next;
}
prev_node->next = min_node->next;

// insert to new list
min_node->next = NULL;
last->next = min_node;
last = min_node;
}
return n_dummy->next;
}
};