POJ 2503 快速排序+二分 / 哈希查找

快速排序+二分：

#include <iostream>
#include <cstdio>
#include <fstream>
#include <algorithm>
#include <cmath>
#include <deque>
#include <vector>
#include <queue>
#include <string>
#include <cstring>
#include <map>
#include <stack>
#include <set>

typedef long long int ll;

#define PI 3.14159265358979323846
#define INF 0x3f3f3f3f
#define INFLL 0x3f3f3f3f3f3f3f3fll
#define maxn 100000+5
#define mod 2000120420010122
#define eps 1e-7

using namespace std;

typedef struct{
    char english[11];
    char foreign[11];
}node;
node a[maxn];

int cnt=0;

int cmp(const void *a, const void *b){
    return strcmp((*(node *)a).foreign, (*(node *)b).foreign);
}

int BinSearch(char str[]){
    int left=0, right=cnt-1;
    int mid, tmp;
    while(left<=right){
        mid=(left+right)/2;
        tmp=strcmp(str, a[mid].foreign);
        if(tmp==0){        //
            return mid;
        }else if(tmp>0){
            left=mid+1;
        }else{
            right=mid-1;
        }
    }
    return -1;
}

int main(int argc, char const *argv[]){
    char str[25];
    while(gets(str)){
        if(str[0]=='\0')
            break;
        
        sscanf(str,"%s%s",a[cnt].english,a[cnt].foreign);
        cnt++;
    }
    qsort(a, cnt, sizeof(a[0]), cmp);
    /*
    for(int i=0;i<cnt;i++){
        cout<<a[i].english<<" "<<a[i].foreign<<endl;
    }
     */
    int flag=-1;
    while(gets(str)){
        //cout<<str<<endl;
        flag=BinSearch(str);
        if(flag==-1){
            printf("eh\n");
        }else{
            printf("%s\n",a[flag].english);
        }
    }
    
}

哈希：

#include <iostream>
#include <cstdio>
#include <fstream>
#include <algorithm>
#include <cmath>
#include <deque>
#include <vector>
#include <queue>
#include <string>
#include <cstring>
#include <map>
#include <stack>
#include <set>

typedef long long int ll;

#define PI 3.14159265358979323846
#define INF 0x3f3f3f3f
#define INFLL 0x3f3f3f3f3f3f3f3fll
#define maxn 149993
#define eps 1e-7

using namespace std;

int ELFhash(char *key){//
    unsigned long h=0;
    while(*key){
        h=(h<<4)+(*key++);
        unsigned long g = h & 0Xf0000000L;//
        if(g){
            h ^= g>>24;
        }
        h &= ~g;
    }
    return h % maxn;
}

typedef struct{
    char english[11];
    char foreign[11];
    int next;
}node;

node a[maxn];
int cnt=1;
int hashIndex[maxn];

void solve(char f[]){
    int hash=ELFhash(f);
    for(int k = hashIndex[hash]; k; k = a[k].next){
        if(strcmp(f, a[k].foreign) == 0){
            printf("%s\n",a[k].english);
            return;
        }
    }
    printf("eh\n");
}

int main(int argc, char const *argv[]){
    char str[25];
    while(gets(str)){
        if(str[0]=='\0'){
            break;
        }
        sscanf(str, "%s%s",a[cnt].english,a[cnt].foreign);
        int hash=ELFhash(a[cnt].foreign);
        a[cnt].next=hashIndex[hash];
        hashIndex[hash]=cnt;
        cnt++;
    }
    while(gets(str)){
        solve(str);
    }
}