剑指offer系列源码-两个链表的第一个公共结点

两个链表的第一个公共结点

两个链表相交成Y型。

#include <iostream>#include <stdio.h>using namespace std;struct ListNode{    int value;    ListNode* next;};unsigned int getListLength(ListNode* pHead){    unsigned int length = 0;    ListNode* pNode = pHead;    while(pNode){        length++;        pNode = pNode->next;    }    return length;}ListNode* findFirstCommonNode(ListNode* pHead1,ListNode* pHead2){    unsigned int length1 = getListLength(pHead1);    unsigned int length2 = getListLength(pHead2);    int lengthDif = length1-length2;    ListNode* pListHeadLong = pHead1;    ListNode* pListHeadShort = pHead2;    if(length1<length2){        pListHeadLong = pHead2;        pListHeadShort = pHead1;        lengthDif =length2-length1;    }    for(int i=0;i<lengthDif;i++){        pListHeadLong = pListHeadLong->next;    }    while(pListHeadLong&&pListHeadShort&&pListHeadLong!=pListHeadShort){        pListHeadLong = pListHeadLong->next;        pListHeadShort = pListHeadShort->next;    }    ListNode* pFirstCommonNOde = pListHeadLong;    return pFirstCommonNOde;}int main() {return 0;}