[大模拟]两种方式解决Chat（UVALive-7047）大模拟

Part 1:题目地址

1.UVALive Chat UVALive - 7047
2.Virtual Judge Chat UVALive - 7047
3.HDU Chat UVALive - 7047

Part 2:解题思路和注意点

大模拟题的关键是使用的工具和编码的严谨，由题意可以得到这个模拟题有很多插入，删除，更换位置，访问的操作，这些操作的总数不是很多，所以时间复杂度的问题可以放在后面，主要问题是实现这些功能。

我的做法是使用链表来完成这个模拟题，链表虽然写起来比较麻烦，但是只要注意指针的方向，及时控制好释放空间，运用模块化的思想，可以大大减少代码量（当然相对于使用STL模板来说代码量肯定还是多的）。

Chat这个题主要是九个操作：

1.Add u:

在队列末尾增加一个priority为u的人，如果这人已经在队列里面，就输出same priority，否则输出success.

2.Close u:

在队列中删除一个priority为u的人，如果这个人不在队列里面，就输出invalid priority，否则输出success.

3.Chat w:

与队列第一个人聊w句话，注意，如果存在有top标记的人，则要和这个人说w句，而不是队列第一个人，如果队列为空就是empty，否则输出success.

4.Rotate x:

将队列中第x人移到队列的第一个位置，如果x大于队列人数，就输出out of range，否则输出success

5.Prior:

将队列中priority最高的人移到队列的第一个位置，如果队列为空就是empty，否则输出success.

6.Choose x:

将队列中priority为x的人移到队列的第一个位置，如果这个人不在队列里面，就输出invalid priority，否则输出success.

7.Top x:

将队列中priority为x的人设置为Top，如果这个人不在队列里面，就输出invalid priority，否则输出success.

8.Untop:

取消当前的Top标记，如果当前没有Top标记，就输出no such person，否则输出success.

9.bey(末尾处理):

在结尾，如果队列中还有人，主人公要和所以说过话的人说bey，如果有Top标记的人，就要先和这个人说bey，然后再和其他人说bey。

这些操作主要是标记和更换队列比较有难度，我选择使用map来标记这个人是否在队列中，然后使用链表来模拟队列的情况，同时还有一个Top标记初始值设置为0，如果有了Top操作则设置为该人的priority值。

注意点:
1.Close操作的时候，如果删除的人有top标记，一定要记得还原top标记。
2.可以利用Map的迭代器来找到队列中priority最大的人。

Part 3:代码部分

链表写法

#include<bits/stdc++.h>#define MAXN 100010#define MAXE 100010#define ll long long#define eps 1e-6#define PI acos(-1)#define FILEIN freopen("in.txt","r",stdin)#define FILEOUT freopen("out.txt","w",stdout)#define CLR(x) memset(x,0,sizeof(x))#define MEM(a,x) memset(a,x,sizeof(a))#define PB(x) push_back(x)#define PF(x) push_front(x)#define rep(x,a,b) for(x=a;x<b;x++)void sf(int &x){scanf("%d",&x);}void sf(char &x){scanf("%c",&x);}void sf(double &x){scanf("%lf",&x);}void sf(char *x){scanf("%s",x);}void sf(ll &x){scanf("%I64d",&x);}void pf(int x){printf("%d",x);}void pf(char x){printf("%c",x);}void pf(double x){printf("%f",x);}void pf(char *x){printf("%s",x);}void pf(ll x){printf("%I64d",x);}void pf(){printf("\n");}const ll mod = 1e9+7;const int maxn = 100010;const int INF = 0x7ffffff;const long long LINF = 0x7fffffffffffffff;using namespace std;ll q_pow(ll x,ll y){ll res=1;while(y){if(y&1) res=(res*x)%mod; y>>=1;x=(x*x)%mod;}return res;}ll inv(ll x){return q_pow(x,mod-2);}int Read(){int x=0,F=1;char C=getchar();while(C<'0'||C>'9'){if(C=='-')F=-F;C=getchar();}while(C>='0'&&C<='9'){x=x*10-'0'+C,C=getchar();}return x*F;}int Trans(){char c;sf(c);int res;res=c-'0';return res;}map<int,int>M;map<int,int>::iterator it;int TOPflag=0,LEN=0;struct girls{    int pri;int w;    girls *next;}*head;girls*newnode(int x){    girls*p;    p=(girls*)malloc(sizeof(girls));    p->pri = x;p->w = 0;p->next=NULL;    return p;}void Add(int u){    if(M[u]==1){printf("same priority.\n");return ;}    else{        if(head == NULL){            girls *tem;            tem = newnode(u);            head = tem;        }        else{            girls *tem,*p;            tem = newnode(u);p=head;            while(p->next!=NULL){p=p->next;}            p->next = tem;        }        M[u]=1;LEN++;        printf("success.\n");    }    return ;}void Close(int u){    if(M[u] == 0){printf("invalid priority.\n");return ;}    else    {        girls *pre,*tem;        pre = tem = head;        while(1){            if(tem->pri == u){                if(head==tem){head=head->next;}                pre->next=tem->next;                printf("close %d with %d.\n",tem->pri,tem->w);                if(tem->pri == TOPflag){TOPflag = 0;}                free(tem);                break;            }            else{                pre = tem;tem = tem->next;            }        }        LEN--;M[u]=0;    }    return ;}void Chat(int w){    if(LEN==0){printf("empty.\n");return ;}    else{        if(TOPflag != 0){            girls *tem;tem = head;            while(1){                if(tem->pri == TOPflag){                    tem->w+=w;                    printf("success.\n");                    break;                }                else {tem=tem->next;}            }        }        else{head->w+=w;printf("success.\n");}    }    return ;}void Rotate(int num){    if(num>LEN||num<1){printf("out of range.\n");return ;}    else    {        int cnt=1;girls *tem,*pre;        tem=pre=head;        while(1){            if(cnt == num){                if(num == 1){printf("success.\n");break;}                else{                    pre->next=tem->next;                    tem->next=head;                    head=tem;                    printf("success.\n");                    break;                }            }            else {cnt++;pre=tem;tem=tem->next;}        }    }    return ;}void Prior(){    if(LEN==0){printf("empty.\n");return;}    else{        it=--M.end();        int MAX = (*it).first;        girls *tem,*pre;        tem=pre=head;        while(1){            if(tem->pri == MAX){                if(tem == head){printf("success.\n");break;}                pre->next = tem->next;                tem->next = head;                head = tem;                printf("success.\n");                break;            }            else{pre=tem;tem=tem->next;}        }        return ;    }}void Choose(int u){    if(M[u] == 0){printf("invalid priority.\n");return ;}    else{        girls *tem,*pre;tem=pre=head;        while(1){            if(tem->pri == u){                if(tem == head){printf("success.\n");break;}                pre->next = tem->next;                tem->next = head;                head = tem;                printf("success.\n");                break;            }            else{pre=tem;tem=tem->next;}        }        return ;    }}void Top(int u){    if(M[u] == 0){printf("invalid priority.\n");return ;}    else{TOPflag = u;printf("success.\n");return ;}}void Untop(){    if(TOPflag == 0){printf("no such person.\n");return ;}    else{TOPflag = 0;printf("success.\n");return;}}void GOODBEY(){    if(head == NULL){return ;}    else{        girls *tem,*pre;tem = pre = head;        if(TOPflag !=0){            while(tem->pri!=TOPflag){pre=tem;tem=tem->next;}            if(tem==head){head=head->next;}            else{                pre->next=tem->next;                if(tem->w!=0)                    printf("Bye %d: %d\n",tem->pri,tem->w);                free(tem);            }        }        tem=head;        while(tem != NULL){            if(tem->w!=0)                printf("Bye %d: %d\n",tem->pri,tem->w);            girls *p;p=tem;            tem=tem->next;            free(p);        }    }    return ;}/*void show(){    if(head == NULL) return ;    girls *tem;    tem = head;    while(tem!=NULL){        printf("%d-%d\n",tem->pri,tem->w);        tem=tem->next;    }    printf("\n");}*/int main(){    int T;cin>>T;    while(T--){        head=NULL;TOPflag=0,LEN=0;        int n,opid;cin>>n;        M.clear();        rep(opid,1,n+1){            //show();            string opname;int num;            cin>>opname;            cout<<"Operation #"<<opid<<": ";            if(opname == "Add"){cin>>num;Add(num);}            if(opname == "Close"){cin>>num;Close(num);}            if(opname == "Chat"){cin>>num;Chat(num);}            if(opname == "Rotate"){cin>>num;Rotate(num);}            if(opname == "Prior"){Prior();}            if(opname == "Choose"){cin>>num;Choose(num);}            if(opname == "Top"){cin>>num;Top(num);}            if(opname == "Untop"){Untop();}        }        GOODBEY();    }    return 0;}

当然如果是使用列表则STL中的Vector也可以取代使用。
下面是STL版本：

#include<bits/stdc++.h>#define MAXN 100010#define MAXE 100010#define ll long long#define eps 1e-6#define PI acos(-1)#define FILEIN freopen("in.txt","r",stdin)#define FILEOUT freopen("out.txt","w",stdout)#define CLR(x) memset(x,0,sizeof(x))#define MEM(a,x) memset(a,x,sizeof(a))#define PB(x) push_back(x)#define PF(x) push_front(x)#define rep(x,a,b) for(x=a;x<b;x++)void sf(int &x){scanf("%d",&x);}void sf(char &x){scanf("%c",&x);}void sf(double &x){scanf("%lf",&x);}void sf(char *x){scanf("%s",x);}void sf(ll &x){scanf("%I64d",&x);}void pf(int x){printf("%d",x);}void pf(char x){printf("%c",x);}void pf(double x){printf("%f",x);}void pf(char *x){printf("%s",x);}void pf(ll x){printf("%I64d",x);}void pf(){printf("\n");}const ll mod = 1e9+7;const int maxn = 100010;const int INF = 0x7ffffff;const long long LINF = 0x7fffffffffffffff;using namespace std;ll q_pow(ll x,ll y){ll res=1;while(y){if(y&1) res=(res*x)%mod; y>>=1;x=(x*x)%mod;}return res;}ll inv(ll x){return q_pow(x,mod-2);}int Read(){int x=0,F=1;char C=getchar();while(C<'0'||C>'9'){if(C=='-')F=-F;C=getchar();}while(C>='0'&&C<='9'){x=x*10-'0'+C,C=getchar();}return x*F;}int Trans(){char c;sf(c);int res;res=c-'0';return res;}map<int ,ll>M;map<int ,ll>::iterator iter;vector<int >V;vector<int >::iterator it;string opname;int TOP =  0;void init(){M.clear();V.clear();TOP=0;}void Add(int t){    if(M.find(t)!=M.end()){printf("same priority.\n");return;}    V.push_back(t);M[t]=0;printf("success.\n");}void Close(int t){    if(M.find(t)==M.end()){printf("invalid priority.\n");return;}    printf("close %d with %lld.\n",t,M[t]);    if(TOP==t){TOP=0;}    it=find(V.begin(),V.end(),t);V.erase(it);M.erase(t);}void Chat(int t){    if(V.empty()){printf("empty.\n");return ;}    if(TOP) M[TOP]+=t;    else{        it=V.begin();        M[(*it)]+=t;    }    printf("success.\n");}void Rotate(int t){    if(t<1||t>V.size()){printf("out of range.\n");return ;}    it=V.begin()+(t-1);    int girl=(*it);V.erase(it);    V.insert(V.begin(),girl);    printf("success.\n");}void Prior(){    if(M.empty()){printf("empty.\n");return;}    iter=--M.end();    int girl=(*iter).first;    it=find(V.begin(),V.end(),girl);    V.erase(it);V.insert(V.begin(),girl);    printf("success.\n");}void Choose(int t){    if(M.find(t) == M.end()){printf("invalid priority.\n");return ;}    it=find(V.begin(),V.end(),t);    V.erase(it);    V.insert(V.begin(),t);    printf("success.\n");}void Top(int t){    if(M.find(t) == M.end()){printf("invalid priority.\n");return ;}    TOP=t;printf("success.\n");return ;}void Untop(){    if(TOP==0){printf("no such person.\n");return;}    TOP=0;printf("success.\n");return;}int main(){    int cas,n,num;    cin>>cas;    while(cas--){        init();        cin>>n;        for(int i=1;i<=n;i++){            cin>>opname;            printf("Operation #%d: ",i);            if(opname == "Add"){cin>>num;Add(num);}            if(opname == "Close"){cin>>num;Close(num);}            if(opname == "Chat"){cin>>num;Chat(num);}            if(opname == "Rotate"){cin>>num;Rotate(num);}            if(opname == "Prior"){Prior();}            if(opname == "Choose"){cin>>num;Choose(num);}            if(opname == "Top"){cin>>num;Top(num);}            if(opname == "Untop"){Untop();}        }        if(TOP!=0){            it = find(V.begin(),V.end(),TOP);            if(M[(*it)]>0) printf("Bye %d: %lld\n",(*it),M[(*it)]);            V.erase(it);        }        for(it=V.begin();it!=V.end();it++){            if(M[(*it)]>0) printf("Bye %d: %lld\n",(*it),M[(*it)]);        }    }    return 0;}