poj2503 hash

src:http://poj.org/problem?id=2503

 

ac代码：

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<stdio.h>
#include <cstdlib>
#include<malloc.h>
#include<algorithm>
#include<functional>
#include<utility>
#include<cmath>
#include<Map>
#include<string.h>
#include<string>
#include<vector>
#include<stack>
#include<set>
#include<queue>
#include<list>
#define FOR(i,a,b) for(int i=a;i<=b;i++)
using namespace std;
#define siz 100005
#define inf 99999999
struct
{
    char s1[11], s2[11];
    int ne;
}node[siz];
int hashmap[siz];
char ans[11];
int Enum;
void init()
{
    Enum = 0;
    memset(hashmap, -1, sizeof(hashmap));
}
unsigned int ELF_hash(char*s)
{
    unsigned int hash = 0, x = 0;
    while (*s) {
        hash = (hash << 4) + (*s);//hash左移4位加上*s
        x = hash & 0xf0000000L;//取出高四位
        if (x != 0) {
            hash ^= x >> 24;//用高四位来处理5-8位，低四位刚来不要搞他先~~~
                            //抑或0时不变，抑或1时变
            hash &= ~x;
        }
        s++;
    }
    return hash % 10001;
}
void Insert_Hash(char*s1, char*s2)
{
    int key = ELF_hash(s2);
    strcpy(node[Enum].s1, s1);
    strcpy(node[Enum].s2, s2);
    node[Enum].ne = hashmap[key];
    hashmap[key] = Enum++;
}
int find(char *t)
{
    int key = ELF_hash(t);
    bool flag = false;
    for (int i = hashmap[key]; i != -1; i = node[i].ne) {
        if (strcmp(node[i].s2, t)==0) {
            flag = true; return i;
        } 
    }
    if (!flag)return -1;
}
void solve()
{
    char t[11];
    while (cin >> t) {
        int ee = find(t);
        if (ee == -1)cout << "eh" << endl;
        else cout << node[ee].s1 << endl;
    }
}
int main()
{
    ios::sync_with_stdio(false);
    char s1[11], s2[11], str[22];
    init();
    while (cin.getline(str, 22)) {//cin>>string会跳过空行，，单独读取一整行就不会，上一行已经把他自己的换行符吃了
        if (str[0] == '\0')break;  //\0 空
        sscanf(str, "%s %s", s1, s2);
        Insert_Hash(s1, s2);
    }
    solve();
    return 0;
}