hdu 1058 Humble Numbers

原题链接：http://acm.hdu.edu.cn/showproblem.php?pid=1058 
优先队列的应用，如下：

 1 #include<functional>

 2 #include<algorithm>

 3 #include<iostream>

 4 #include<cstdlib>

 5 #include<cstdio>

 6 #include<vector>

 7 #include<queue>

 8 using std::vector;

 9 using std::greater;

10 using std::priority_queue;

11 typedef unsigned long long ull;

12 const int Max_N = 5843;

13 ull ans[Max_N];

14 void init() {

15     int arr[5] = { 2, 3, 5, 7 };

16     priority_queue<ull, vector<ull>, greater<ull> > que;

17     que.push(1);

18     for (int i = 1; i <= Max_N;) {

19         ull t = que.top();

20         que.pop(), ans[i] = t;

21         if (ans[i] == ans[i - 1]) {

22             continue;

23         } else {

24             i++;

25         }

26         for (int j = 0; j < 4; j++) que.push((ull)(t * arr[j]));

27     }

28 }

29 int main(){

30     init();

31     int n;

32     while (~scanf("%d", &n) && n) {

33         if (n % 10 == 1 && n % 100 != 11) 

34             printf("The %dst humble number is %lld.\n", n, ans[n]);

35         else if (n % 10 == 2 && n % 100 != 12) 

36             printf("The %dnd humble number is %lld.\n", n, ans[n]);

37         else if (n % 10 == 3 && n % 100 != 13) 

38             printf("The %drd humble number is %lld.\n", n, ans[n]);

39         else printf("The %dth humble number is %lld.\n", n, ans[n]);

40     }

41     return 0;

42 }

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