HDU 1880 魔咒词典

http://acm.hdu.edu.cn/showproblem.php?pid=1880

最初的想法直接快排+二分查找

为了练习hash就用hash做了

#include <cstdio>
#include <cstring>
using namespace std;

const int N=100010,MAXH=100003;
char w0[N][25],w1[N][85];
int head[2][MAXH],next[2][N];
int n;
int hash(char *key)
{
    unsigned int h=0;
    while(*key)
    {
        h=(h<<4)+*key++;
        unsigned int g=h&0xf000000L;
        if(g) h^=g>>24;
        h&=~g;
    }
    return h%MAXH;
}
void insert(int s,int k)
{
    int h=k?hash(w1[s]):hash(w0[s]);
    next[k][s]=head[k][h];
    head[k][h]=s;
}
void dictionary()
{
    const char end[6]="@END@";
    memset(head,0,sizeof(head));
    memset(next,0,sizeof(next));
    n=0;
    char s1[25],s2[85];
    while(scanf("%s",s1),strcmp(s1,end))
    {
        n++;
        strcpy(w0[n],s1);
        insert(n,0);
        getchar(); gets(s2);
        strcpy(w1[n],s2);
        insert(n,1);
    }
}
int find(char *s,int k)
{
    int h=hash(s);
    int u=head[k][h];
    if(k==0) while(u && strcmp(s,w0[u])) u=next[k][u];
    else while(u && strcmp(s,w1[u])) u=next[k][u];
    return u;
}
void putstr(char *s)
{
    for(int i=1;s[i]!=']';i++) putchar(s[i]);
    putchar('\n');
}
int main()
{
    dictionary();
    int T;
    scanf("%d",&T); getchar();
    while(T--)
    {
        char s[85];
        gets(s);
        if(s[0]=='[')
        {
            int p=find(s,0);
            if(p) puts(w1[p]);
            else puts("what?");
        }
        else
        {
            int p=find(s,1);
            if(p) putstr(w0[p]);
            else puts("what?");
        }
    }
    return 0;
}