11-散列1 电话聊天狂人（25 分）

4
13005711862 13588625832
13505711862 13088625832
13588625832 18087925832
15005713862 13588625832

13588625832 3

思路：一道简单的散列表。取最后5位作为key，冲突时链表插入，相等时计数器加1。

代码：

#include<stdio.h>
#include<string>
long long max = 0, people = 0, id = -1;
struct node {long long date;long long count;struct node *next;
};
typedef struct node * List;
struct hashtable {long long table;List * list;
};
typedef struct hashtable * hash;
typedef struct node * position;
long long nextprime(long long n)
{long long i, j;for (i = n + 1;; i++){for (j = 2; j < i / 2; j++)if (!(i%j)) break;if (j == i / 2) return i;}
}
hash create(long long n)
{hash h = (hash)malloc(sizeof(hashtable));h->table = nextprime(n);h->list = (List *)malloc(sizeof(node)*(int)h->table);for (long long i = 0; i < h->table; i++){h->list[i] = (List)malloc(sizeof(node));h->list[i]->count = 0;h->list[i]->date = 0;h->list[i]->next = NULL;}return h;
}
void insert(hash h, long long key)
{long long k = key % h->table;position p = h->list[k]->next;while (p){if (p->date == key) break;p = p->next;}if (!p){p = (position)malloc(sizeof(node));p->date = key;p->count = 1;p->next = h->list[k]->next;h->list[k]->next = p;}else p->count++;if (p->count > max) {max = p->count;people = 1;id = p->date;}else if (p->count == max) {if (id == -1) id = key;else if (id > key) id = key;people++;}
}
void searchAndOut(hash h)
{if (people == 1) printf("%lld %lld\n", id, max);else printf("%lld %lld %lld\n", id, max, people);
}
int main()
{long long n, a, b;scanf("%lld", &n);hash h = create(2 * n);for (long long i = 0; i < n; i++){scanf("%lld %lld", &a, &b);insert(h, a);insert(h, b);}searchAndOut(h);
}

结尾：本来直接想把散列表定义拷上去的，但是学校网站进不去了。于是准备手撸一个，结果一路顺畅 (*^▽^*)

交上去以后最后一个测试点过不去，很郁闷，查了半个多小时才发现 把'>' 写成 ‘<’     (╯‵□′)╯︵┻━┻

现在想想完全可以定义一个struct node，然后用vector实现……下次有空试试