leetcode/Problem23.java at master · actor168/leetcode · GitHub

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publicclassProblem23 {
publicstaticvoidmain(String[] args) {
ListNodea = newListNode(1);
a.next = newListNode(4);
a.next.next = newListNode(5);

ListNodeb = newListNode(0);
b.next = newListNode(3);
b.next.next = newListNode(4);

ListNodec = newListNode(2);
c.next = newListNode(6);

ListNode[] lists = newListNode[]{a, b, c};

ListNoderes = newProblem23().mergeKLists(lists);
ListNodep = res;
for (; p.next != null ; p=p.next) {
System.out.print(p.val + "->");
 }
System.out.print(p.val);

	}

publicListNodemergeKLists(ListNode[] lists) {
intinterval = 1;
while (interval < lists.length) {
for(inti = 0; i < lists.length - interval; i += interval * 2) {
lists[i] = merge2Lists(lists[i], lists[interval + i]);
 }
interval *= 2;
 }

returnlists[0];
 }

// merge 2 lists
ListNodemerge2Lists(ListNodel1, ListNodel2) {
ListNodep = l1;
ListNodeq = l2;
ListNodepre = null;
while (p!= null && q != null) {
if(q.val < p.val) {
// insert q before p
ListNodetmp = q.next;
if (pre != null) {
pre.next = q;
pre = q;
 }
else {
pre = q;
l1 = pre;
 }
pre.next = p;
q=tmp;
 } else {
pre = p;
p = p.next;
 }
 }

if (p == null) {
if (pre != null) {
pre.next = q;
 } else {
pre = q; l1 =pre;
 }
 }
returnl1;
 }
}


classListNode {
intval;
ListNodenext;
ListNode(intx) { val = x; }
}