DAY4| 24. 两两交换链表中的节点、19.删除链表的倒数第N个节点、面试题 02.07. 链表相交、142.环形链表II

public ListNode getIntersectionNode(ListNode headA, ListNode headB) {

if(headA==null || headB==null) return null;

ListNode curA = headA;

ListNode curB = headB;

int countA = 0;

int countB = 0;

while(curA!=null){

countA++;

curA = ;

}

while(curB!=null){

countB++;

curB = ;

}

int sub=0;

if(countA>=countB){

sub = countA-countB;

}else{

ListNode temp = headA;

headA = headB;

headB = temp;

sub = countB-countA;

}

curA = headA;

curB = headB;

while(sub!=0){

headA = ;

sub--;

}

while(headA!=null){

if(headA==headB) return headA;

headA = ;

headB = ;

}

return null;

}