PAT_A 1028. List Sorting (25)

1028. List Sorting (25)

Excel can sort records according to any column. Now you are supposed to imitate this function.

Input

Each input file contains one test case. For each case, the first line contains two integers N (<=100000) and C, where N is the number of records and C is the column that you are supposed to sort the records with. Then N lines follow, each contains a record of a student. A student’s record consists of his or her distinct ID (a 6-digit number), name (a string with no more than 8 characters without space), and grade (an integer between 0 and 100, inclusive).

Output

For each test case, output the sorting result in N lines. That is, if C = 1 then the records must be sorted in increasing order according to ID’s; if C = 2 then the records must be sorted in non-decreasing order according to names; and if C = 3 then the records must be sorted in non-decreasing order according to grades. If there are several students who have the same name or grade, they must be sorted according to their ID’s in increasing order.
Sample Input 1

3 1
000007 James 85
000010 Amy 90
000001 Zoe 60

Sample Output 1

000001 Zoe 60
000007 James 85
000010 Amy 90

Sample Input 2

4 2
000007 James 85
000010 Amy 90
000001 Zoe 60
000002 James 98

Sample Output 2

000010 Amy 90
000002 James 98
000007 James 85
000001 Zoe 60

Sample Input 3

4 3
000007 James 85
000010 Amy 90
000001 Zoe 60
000002 James 90

Sample Output 3

000001 Zoe 60
000007 James 85
000002 James 90
000010 Amy 90

• 分析：本题就是排序。

  • 利用vector/list algotithm的sort进行排序,最开始用vector结果最后一个用例超时！换成list排序快点，仍是超时！最好查到原来是cin和cout的问题！
  • 尽量少用cin cout ,换成scanf printf

• code:

#include<iostream>#include<algorithm>#include<list>#include<cstdio>#include<cstring>int N;int C;using namespace std;struct IN{    int num;    char name[30];    int score;};list<IN>d;bool comp1(IN a,IN b){    if(a.num<b.num)      return true;    else      return false;}bool comp2(IN a,IN b){    int c=strcmp(a.name,b.name);    if(c<0)      return true;    else if(c>0)      return false;    else    {      if(a.num<b.num)        return true;      else        return false;    }}bool comp3(IN a,IN b){    if(a.score<b.score)      return true;    else if(a.score>b.score)      return false;    else    {      if(a.num<b.num)        return true;      else        return false;    }}int main(){    cin>>N>>C;    IN tmp;    for(int i=0;i<N;i++)    {        /*        长见识了，cin cout太慢，并不是算法的问题        cin>>tmp.num>>tmp.name>>tmp.score;        */        scanf("%d %s %d",                    &tmp.num,                    tmp.name,                    &tmp.score);        d.push_back(tmp);    }    switch(C)    {        case 1:            d.sort(comp1);            break;        case 2:            d.sort(comp2);            break;        case 3:            d.sort(comp3);            break;        default:            break;    }/*    switch(C)    {        case 1:            sort(d.begin(),d.end(),comp1);            break;        case 2:            sort(d.begin(),d.end(),comp2);            break;        case 3:            sort(d.begin(),d.end(),comp3);            break;        default:            break;    }    */    list<IN>::iterator it;    for(it=d.begin();it!=d.end();++it)    {        printf("%06d %s %d\n",                    it->num,                    it->name,                    it->score);    }    return 0;}

• 
  
• 参考
  
  • cin cout 太慢，改用scanf printf