1032 Sharing

代码如下：

#include<iostream>
#include<vector>
#include<algorithm>
#include<stdio.h>
#include<memory.h>
#include<limits>
using namespace std;
int main(){
    int *m = new int[100001];
    int *exist = new int[100001];
    memset(m,-1,sizeof(m));
    memset(exist,-1,sizeof(exist));
    int sum;
    int a,b;
    scanf("%d %d %d",&a,&b,&sum);
    m[a] = -1;
    m[b] = -1;
    for(int i = 0; i < sum; i++){
        char tem[10];
        int pre,next;
        scanf("%d %s %d",&pre,tem,&next);
        m[pre] = next;
    }
    int head = a;
    while(head != -1){
        //把第一个链表存进哈希表exist中
        exist[head] = 1;
        head = m[head];
    }
    head = b;
    while(head != -1){
        if(exist[head] == 1){
            break;
        }
        head = m[head];
    }
    if(head == -1) printf("%d\n",head);
    else printf("%05d\n",head);
    return 0;
}