[Leetcode 160] Intersection of Two Linked Lists

题目

分析

代码

/**
* Definition for singly-linked list.
* struct ListNode {
*     int val;
*     ListNode *next;
*     ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
int getLength(ListNode* head){
int length = 0;
while(head){
length++;
head = head->next;
}
return length;
}
ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
if(headA==NULL || headB==NULL){
return NULL;
}
int lenA = getLength(headA);
int lenB = getLength(headB);
if(lenA >= lenB){
for(int i=lenA-lenB; i>0; headA=headA->next,i--)
;
}else{
for(int i=lenB-lenA; i>0; headB=headB->next,i--)
;
}
for(; headA && headB && headA!=headB; headA=headA->next, headB=headB->next)
;
return (headA==headB)?headA:NULL;
}
};