PAT-AL 1022. Digital Library

1、知识点：字符串比较、排序
2、思路：题目要求结果按照图书编号顺序输出，因此要先将图书排序，然后将搜索词分类比较即可。注意：结构体可以直接赋值，无需重载赋值运算符。

/*用途：
**说明：
**算法：
*/

//#define LOCAL
#include <vector>
#include <cstdio>
#include <string.h>
#include <algorithm>
using namespace std;
struct book{
    char id[10];
    char title[100];
    char author[100];
    char key[5][15];
    char publisher[100];
    char year[10];
    int key_num;
};
vector<book> vec_bo;
vector<int> vec_id;
int N, M;

void to_keywords(book &b, char* s);
bool cmp_id(book b1, book b2);
void query_book(char* s, int type);
bool cmp_keywords(char*s, int ind);
int main()
{
#ifdef LOCAL
    freopen("1022_Digital_Library.in", "r", stdin);
    freopen("1022_Digital_Library.out", "w", stdout);
#endif

    scanf("%d", &N);
    vec_bo.resize(N);
    getchar();                      //读取换行符 
    char buf[100];
    book b;
    for(int i=0; i<N; i++){ 
        gets(b.id);
        gets(b.title);
        gets(b.author);
        gets(buf);                  //提取关键字一行 
        to_keywords(b, buf);        //分割关键字 
        gets(b.publisher);
        gets(b.year);
        vec_bo.at(i) = b;
    }

    sort(vec_bo.begin(), vec_bo.end(), cmp_id);     
    scanf("%d", &M);
    for(int i=0; i<M; i++){
        int type;
        char query[100];
        scanf("%d: ", &type);
        gets(query);
        printf("%d: %s\n", type, query);
        query_book(query, type);
        int num = vec_id.size();
        for(int j=0; j<num; j++)
            printf("%s\n", vec_bo.at(vec_id.at(j)).id);

        if(!num)
            printf("Not Found\n");
    }

    return 0;
}

void to_keywords(book &b, char* s)
{
    char *res = strtok(s, " ");
    b.key_num = 0;
    while(res){
        strcpy(b.key[b.key_num++], res);
        res = strtok(NULL, " ");
    }
}

bool cmp_id(book b1, book b2)
{
    return (strcmp(b1.id, b2.id) <= 0 ? 1 : 0);
}

void query_book(char* s, int type)
{
    vec_id.clear(); 
    for(int i=0; i<N; i++){
        switch(type){
        case(1):
            if(!strcmp(s, vec_bo.at(i).id)){
                vec_id.push_back(i);
                break;
            }
        case(2):
            if(!strcmp(s, vec_bo.at(i).title)){
                vec_id.push_back(i);
                break;
            }
        case(3):
            if(!strcmp(s, vec_bo.at(i).author)){
                vec_id.push_back(i);        
                break;
            }
        case(4):
            if(cmp_keywords(s, i)){
                vec_id.push_back(i);
                break;
            }
        case(5):
            if(!strcmp(s, vec_bo.at(i).publisher)){
                vec_id.push_back(i);
                break;
            }
        case(6):
            if(!strcmp(s, vec_bo.at(i).year)){
                vec_id.push_back(i);
                break;
            }
        default:
            break;
        }
    }
}

bool cmp_keywords(char*s, int ind)
{
    int num = vec_bo.at(ind).key_num;
    for(int i=0; i<num; i++){
        if(!strcmp(s, vec_bo.at(ind).key[i])){
            return 1;
        }
    }

    return 0;
}