Codeforces Beta Round #4 (Div. 2 Only) C. Registration system 暴力or 字典树or哈希

http://codeforces.com/problemset/problem/4/C

题意：

一个注册系统，给出n个注册的名字，每次检查数据库中是否存在该名字，如果不存在返回OK，加入数据库，否如果存在在该名字后边加1,2,3,,,....然后加入数据库。

思路：

暴力存储查询可过，用字典数存处名字可过，哈希存储查找可过。

暴力：

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <string>

#define CL(a,num) memset((a),(num),sizeof(a))
#define iabs(x)  ((x) > 0 ? (x) : -(x))
#define Min(a,b) (a) > (b)? (b):(a)
#define Max(a,b) (a) > (b)? (a):(b)

#define ll long long
#define inf 0x7f7f7f7f
#define MOD 1073741824
#define lc l,m,rt<<1
#define rc m + 1,r,rt<<1|1
#define pi acos(-1.0)
#define test puts("<------------------->")
#define maxn 100007
#define M 1000007
#define N 100007
using namespace std;
//freopen("data.in","r",stdin);


string str[N];
int num[N];
int len;

bool isok(string a,string &b){
    for (int i = 0; i < len; ++i){
        if (str[i] == a){
            char p[10];
            sprintf(p,"%d",num[i]);
            b = a + p;
            num[i]++;
            return false;
        }
    }
    str[len] = a;
    num[len++]++;
    return true;
}
int main(){
    //freopen("data.in","r",stdin);
    int i;
    int n;
    cin>>n;
    string tmp,stre;

    CL(num,0);
    len = 0;
    for (i = 0; i < n; ++i){
        cin>>stre;
        if (isok(stre,tmp)) puts("OK");
        else{
            cout<<tmp<<endl;
        }
    }
    return 0;
}

 

字典数：

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <string>

#define CL(a,num) memset((a),(num),sizeof(a))
#define iabs(x)  ((x) > 0 ? (x) : -(x))
#define Min(a,b) (a) > (b)? (b):(a)
#define Max(a,b) (a) > (b)? (a):(b)

#define ll long long
#define inf 0x7f7f7f7f
#define MOD 1073741824
#define lc l,m,rt<<1
#define rc m + 1,r,rt<<1|1
#define pi acos(-1.0)
#define test puts("<------------------->")
#define maxn 100007
#define M 1000007
#define N 100007
using namespace std;
//freopen("data.in","r",stdin);

struct node{
    int flag;
    node *next[27];
}*head,H[500000];
int t;
char str[40],tmp[10];

node* newnode(){
    node *p = &H[t++];
    for (int i = 0; i < 26; ++i){
        p->next[i] = NULL;
        p->flag = 0;
    }
    return p;
}
bool find(char *s,char *tmp){
    int i,k;
    int len = strlen(s);
    node *p = head;
    for (i = 0; i < len; ++i){
        k = s[i] - 'a';
        if (p->next[k] == NULL) return false;
        p = p->next[k];
    }
    if (p->flag != 0){
        sprintf(tmp,"%d",p->flag);
        p->flag++;
        return true;
    }
    else return false;
}
void insert(char *s){
    int i,k;
    int len = strlen(s);
    node *p = head;
    for (i = 0; i < len; ++i){
        k = s[i] - 'a';
        if (p->next[k] == NULL) p->next[k] = newnode();
        p = p->next[k];
    }
    p->flag++;
}
int main(){
    //freopen("data.in","r",stdin);
    int i;
    int n;
    cin>>n;
    t = 0;

    head = newnode();
    for (i = 0; i < n; ++i){
        scanf("%s",str);
        if (find(str,tmp)) printf("%s%s\n",str,tmp);
        else{
            puts("OK");
            insert(str);
        }
    }
    return 0;
}

 

哈希：

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <string>

#define CL(a,num) memset((a),(num),sizeof(a))
#define iabs(x)  ((x) > 0 ? (x) : -(x))
#define Min(a,b) (a) > (b)? (b):(a)
#define Max(a,b) (a) > (b)? (a):(b)

#define ll long long
#define inf 0x7f7f7f7f
#define MOD 1073741824
#define lc l,m,rt<<1
#define rc m + 1,r,rt<<1|1
#define pi acos(-1.0)
#define test puts("<------------------->")
#define maxn 100007
#define M 1000007
#define N 100007
using namespace std;
//freopen("data.in","r",stdin);

struct node{
    string str;
    int num;
    node *next;
}*head[N + 2],H[N];
int t;
char str[40],tmp[10];

bool Cha(int sum,char *s,char*tmp){
    sum %= N;
    if (sum < 0) sum = -sum;
    node *p;
    for (p = head[sum]; p != NULL; p = p->next){
        if (p->str == s){
            sprintf(tmp,"%d",p->num);
            p->num++;
            return true;
        }
    }
    return false;
}
void Gua(int sum,char *s){
    sum %= N;
    if (sum < 0) sum = -sum;
    node *p = &H[t++];
    p->str = s;
    p->num = 1;
    p->next = head[sum];
    head[sum] = p;
}
int main(){
    //freopen("data.in","r",stdin);
    int n,i,j;
    CL(head,0); t = 0;
    scanf("%d",&n);
    int sum = 0;
    for (i = 0; i < n; ++i){
        scanf("%s",str);
        int len = strlen(str);
        sum = 0;
        for (j = 0; j < len; ++j){
            sum += str[j] - '0';
        }
        if (Cha(sum,str,tmp)) printf("%s%s\n",str,tmp);
        else{
            puts("OK");
            Gua(sum,str);
        }
    }
    return 0;
}