L2-002 链表去重

总结： 要注意条件判断的顺序，分清每一次if所影响的的操作，最后的-1输出在if(cnt)里面，把他写在了外面wa了，非重复的节点也忘了指向下一节点；

#include<algorithm>
#include<set>
#include<vector>
#include<queue>
#include<cmath>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<set>
#include<vector>
#include<queue>
#include<cmath>
#include<cstring>
#include<sstream>
#include<cstdio>
#include<ctime>
#include<map>
#include<stack>
#include<string>
using namespace std;

#define sfi(i) scanf("%d",&i)
#define pri(i) printf("%d\n",i)
#define sff(i) scanf("%lf",&i)
#define ll long long
#define mem(x,y) memset(x,y,sizeof(x))
#define INF 0x3f3f3f3f
#define eps 1e-6
#define PI acos(-1)
#define lowbit(x) ((x)&(-x))
#define zero(x) (((x)>0?(x):-(x))<eps)
#define fl() printf("flag\n")
ll gcd(ll a,ll b){while(b^=a^=b^=a%=b);return a;}
const int maxn=1e6+9;
const int mod=1e9+7;

template <class T>
inline void sc(T &ret)
{
    char c;
    ret = 0;
    while ((c = getchar()) < '0' || c > '9');
    while (c >= '0' && c <= '9')
    {
        ret = ret * 10 + (c - '0'), c = getchar();
    }
}

ll power(ll n,ll x)
{
    ll ans=1;
    while(n)
    {
        if(n&1) ans=ans*x;
        n>>=1;
        x=x*x;
    }
    return ans;
}

struct node
{
    int nx;
    int x;
}p[maxn];

bool vis[maxn];
int us[maxn];
int cnt=0;
int main()
{
    int n,st;
    cin>>st>>n;
    for(int i=0;i<n;i++)
    {
        int id;
        cin>>id;
        cin>>p[id].x>>p[id].nx;
    }
    printf("%05d %d ",st,p[st].x);
    vis[abs(p[st].x)]=1;
    st=p[st].nx;
    while(1)
    {
        if(st!=-1)
        {
            if(vis[abs(p[st].x)])
            {
                //cout<<st<<endl;
                us[cnt++]=st;
                st=p[st].nx;
            }
            else
            {
                printf("%05d\n%05d ",st,st);
                printf("%d ",p[st].x);
                vis[abs(p[st].x)]=1;
                st=p[st].nx;
            }

        }
        else
        {
            cout<<-1<<endl;
            break;
        }
    }
    /*for(int i=0;i<cnt;i++)
    {
        //cout<<us[i]<<" ";
    }*/
    if(cnt)
    {
        printf("%05d ",us[0]);
        cout<<p[us[0]].x<<" ";
        for(int i=1;i<cnt;i++)
        {
            printf("%05d\n%05d ",us[i],us[i]);
            cout<<p[us[i]].x<<" ";
        }
        cout<<-1<<endl;
    }
    return 0;
}