PAT 乙级 1028 人口普查

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解题思路：此题我想到俩种方法，一种是排序方法，一种是不排序的方法，首先都是看是否是有效年龄，然后一种是排序，另一种是维护最大值和最小值的变量，一定要注意如果有效数字是0那就只输出0就可以了。

c语言解法一：排序法

#include<stdio.h>
typedef struct
{char name[6];int year;int month;int day;
}old_man;
int valid(old_man m)
{if(m.year>2014||m.year<2014-200)return 0;if(m.year==2014&&(m.month>9||(m.month==9&&m.day>6))){return 0;}if(m.year==2014-200&&(m.month<9||(m.month==9&&m.day<6)))return 0;return 1;	
}
int compare(old_man a,old_man b)
{if(a.year!=b.year)return b.year-a.year;if(a.month!=b.month)return b.month-a.month;return b.day-a.day;
}
int main()
{int n,youxiao=0,i;old_man max,min,current,temp;max.day=31,max.year=2015,max.month=12;min.day=0,min.year=0,min.month=0;scanf("%d",&n);for(i=0;i<n;i++){scanf("%s %d/%d/%d",current.name,&(current.year),&(current.month),&(current.day));if(valid(current))youxiao++;elsecontinue;if(compare(max,current)<0){max=current;}if(compare(current,min)<0){min=current;}}if(youxiao)printf("%d %s %s\n",youxiao,max.name,min.name);elseprintf("%d\n",youxiao);return 0;
}

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c语言解法二不排序：

#include<stdio.h>
typedef struct
{char name[6];int year;int month;int day;
}old_man;
int valid(old_man m)
{if(m.year>2014||m.year<2014-200)return 0;if(m.year==2014&&(m.month>9||(m.month==9&&m.day>6))){return 0;}if(m.year==2014-200&&(m.month<9||(m.month==9&&m.day<6)))return 0;return 1;	
}
int compare(old_man a,old_man b)
{if(a.year!=b.year)return b.year-a.year;if(a.month!=b.month)return b.month-a.month;return b.day-a.day;
}
int main()
{int n,youxiao=0,i;old_man max,min,current,temp;max.day=31,max.year=2015,max.month=12;min.day=0,min.year=0,min.month=0;scanf("%d",&n);for(i=0;i<n;i++){scanf("%s %d/%d/%d",current.name,&(current.year),&(current.month),&(current.day));if(valid(current))youxiao++;elsecontinue;if(compare(max,current)<0){max=current;}if(compare(current,min)<0){min=current;}}if(youxiao)printf("%d %s %s\n",youxiao,max.name,min.name);elseprintf("%d\n",youxiao);return 0;
}