/*
struct ListNode {
int val;
struct ListNode
*next;
ListNode(
int x) :
val(
x),
next(NULL) {
}
};
*/
class Solution {
public:
ListNode* FindFirstCommonNode( ListNode* pHead1, ListNode* pHead2) {
ListNode * p = pHead1;
int num1 =
0;
int num2 =
0;
while (p)
{
num1++;
p = p->
next;
}
ListNode
*p2 = pHead2;
while(p2)
{
num2++;
p2 = p2->
next;
}
if (num2>num1)
{
int x = num2-num1;
for (
int i =
0 ; i!=
x ; i++)
{
pHead2=pHead2->
next;
}
while (pHead2)
{
if (pHead2->val == pHead1->val)
return pHead2;
pHead2 = pHead2->
next;
pHead1 = pHead1->
next;
}
}
else{
int x = num1 - num2;
for (
int i =
0; i!=
x;i++)
{
pHead1 = pHead1->
next;
}
while (pHead1)
{
if (pHead1->val == pHead2->val)
return pHead1;
pHead1 = pHead1->
next;
pHead2 = pHead2->
next;
}
}
return NULL;
}
};
