DS Bonus 2: QQ Account Management

题目要求

You are supposed to implement the functions of account"Log in" and "Register" for the most popular instantmessager QQ.  The most challenging partis that QQ now has more than a billion users.

 

Input Specification:

Each input file contains one test case.  For each case, the first line contains anintegerN (£10⁵) - the total number ofqueries.  Then N lines follow, each contains a query in the format:

Command QQ_No Password

where "Command" is either"R" (meaning to register a new account, and hence followed by a newaccount number and a password), or "L" (meaning to log in with anexisting account, and hence followed by the account number and the password);"QQ_No" is an integer that is greater than 1000 and no more than 10digits long; and "Password" is a string with no less than 6 and nomore than 16 characters without any space.

 

Output Specification:

For each test case, print the correspondingmessage for each query in a line.  Themessages are:

l  If a new account is successfullyregistered, output "Register Successful";

l  If the new registering account numberalready exists, output "ERROR: Account Number Already Exists";

l  If log in successfully, output "Log inSuccessful";

l  If the log in account does not exist, output"ERROR: Account Not Exist";

l  If log in with a wrong password, output"ERROR: Wrong Password".

 

Sample Input:

5

L 1234567890 [e-mail]

R 1234567890 [e-mail]

R 1234567890 [e-mail]

L 1234567890 myQQ@qq

L 1234567890 [e-mail]

 

Sample Output:

 

ERROR: Account Not Exist

Register Successful

ERROR: Account Number Already Exists

ERROR: Wrong Password

Log in Successful

 

哈希法

#include<stdio.h>#include<stdlib.h>#include<string.h>#define MinTableSize 5typedef struct QQ* Database; typedef struct HashEntry Cell;typedef struct HashT *HashTable;struct QQ{char id[15];char password[20];};enum KindOfEntry{Legitimate,Empty,Deleted};struct HashEntry{struct QQ user;enum KindOfEntry Info;};struct HashT{int tablesize;Cell *thecells;};int Isprime(int n){int i;if(n == 1)return 0;for(i = 2;i*i<=n;i++)if(n %i == 0)break;if(i*i<=n)return 0;else return 1;}int nextprime(int n){while(!Isprime(n)){n++;}return n;}int Hash(const char *key,int n){int hashval;hashval = 0;while(*key != '\0'){hashval = (hashval << 1) + *key++;}return hashval % n;}HashTable Initialize(int tablesize){HashTable h;int i;if(tablesize<MinTableSize){perror("Table size too small\n");return NULL;}h = (HashTable)malloc(sizeof(struct HashT));if(h == NULL){perror("Out of Space\n");return NULL;}h->tablesize = nextprime(tablesize);h->thecells = (Cell*)malloc(sizeof(Cell)*h->tablesize);if(h->thecells == NULL){perror("Out of Space\n");return NULL;}for(i = 0;i<h->tablesize;i++)h->thecells[i].Info = Empty;return h;}int Find(char *key,HashTable h){int currentpos;int collisionnum;collisionnum = 0;currentpos = Hash(key,h->tablesize);while(h->thecells[currentpos].Info != Empty&&strcmp(h->thecells[currentpos].user.id,key)){currentpos += 2*++collisionnum-1;if(currentpos>=h->tablesize)currentpos -= h->tablesize;}return currentpos;}void Insert(struct QQ key,HashTable h){int pos;pos = Find(key.id,h);if(h->thecells[pos].Info!=Legitimate){h->thecells[pos].Info = Legitimate;h->thecells[pos].user = key;}}struct QQ *findcount(HashTable h,char *count){int pos;pos = Find(count,h);if(h->thecells[pos].Info == Empty)return NULL;else return &h->thecells[pos].user;}void CountInsert(HashTable h,char *count,char *pwd){struct QQ user;strcpy(user.id,count);strcpy(user.password,pwd);Insert(user,h);}HashTable ReHash(HashTable h){Cell *oldcells;int oldsize,i;oldcells = h->thecells;oldsize = h->tablesize;h = Initialize(oldsize*2);for(i = 0;i<oldsize;i++)if(oldcells[i].Info == Legitimate)Insert(oldcells[i].user,h);free(oldcells);return h;}int main(){Database r,d,p;int n,size;HashTable h;char cmd,count[15],pwd[20],*s;scanf("%d",&n);getchar();r = NULL;size = 0;h = Initialize(100000);while(n--){scanf("%c%s%s",&cmd,&count,&pwd);getchar();d = findcount(h,count);if(cmd == 'L'){if(d == NULL)printf("ERROR: Account Not Exist\n");else if(strcmp(d->password,pwd))       printf("ERROR: Wrong Password\n"); else printf("Log in Successful\n");    }     else if(cmd == 'R') {    if(d != NULL)    printf("ERROR: Account Number Already Exists\n");    else{    printf("Register Successful\n");      CountInsert(h,count,pwd);      size++;      //if(size == h->tablesize/2)      //h = ReHash(h);    }    }}return 0;}

AVL TREE

#include<stdio.h>#include<stdlib.h>#include<string.h>typedef struct QQ* Database; struct QQ{char id[15];char password[20];int height;Database left,right;};//Tree searchDatabase findcount(Database d,char *id){while(d != NULL){if(strcmp(id,d->id) == 0) break;else if(strcmp(id,d->id)<0) d = d->left;else if(strcmp(id,d->id)>0) d = d->right;    }    return d;}//AVL treeint height(Database r){if(r == NULL)return -1;else return r->height;}Database SingleRotateWithLeft(Database p){Database q;q = p->left;p->left  = q->right;q->right = p;p->height = height(p->left)>height(p->right)?height(p->left) + 1:height(p->right) + 1;q->height = height(q->left)>height(q->right)?height(q->left) + 1:height(q->right) + 1;return q;}Database SingleRotateWithRight(Database p){Database q;q = p->right;p->right  = q->left;q->left = p;p->height = height(p->left)>height(p->right)?height(p->left) + 1:height(p->right) + 1;q->height = height(q->left)>height(q->right)?height(q->left) + 1:height(q->right) + 1;return q;}Database DoubleRotateWithLeft(Database p){p->left = SingleRotateWithRight(p->left);return SingleRotateWithLeft(p);}Database DoubleRotateWithRight(Database p){p->right = SingleRotateWithLeft(p->right);return SingleRotateWithRight(p);}Database treeinsert(Database r,char *id,char *pwd){Database p;if(r == NULL){r = (Database)malloc(sizeof(struct QQ));if(r == NULL){printf("Out of Space\n");return NULL;}strcpy(r->id,id);strcpy(r->password,pwd);          r->left = r->right = NULL;        r->height = 0;  }else if(strcmp(id,r->id)<0){r->left = treeinsert(r->left,id,pwd);if(height(r->left) - height(r->right) == 2)if(strcmp(id,r->left->id)<0)r = SingleRotateWithLeft(r);else r = DoubleRotateWithLeft(r);}else if(strcmp(id,r->id)>0){r->right = treeinsert(r->right,id,pwd);if(height(r->right) - height(r->left) == 2)if(strcmp(id,r->right->id)>0)r = SingleRotateWithRight(r);else r = DoubleRotateWithRight(r);}r->height = height(r->left)>height(r->right)?height(r->left)+1:height(r->right)+1;return r;}int main(){Database r,d,p;int n;char cmd,count[15],pwd[20],*s;scanf("%d",&n);getchar();r = NULL;while(n--){scanf("%c%s%s",&cmd,&count,&pwd);getchar();d = findcount(r,count);if(cmd == 'L'){if(d == NULL)printf("ERROR: Account Not Exist\n");else if(strcmp(d->password,pwd))       printf("ERROR: Wrong Password\n"); else printf("Log in Successful\n");    }     else if(cmd == 'R') {    if(d != NULL)    printf("ERROR: Account Number Already Exists\n");    else{    printf("Register Successful\n");        r = treeinsert(r,count,pwd);    }    }}return 0;}