HNU 12876 Quite Good Numbers 完美数变形

筛法是一种很快的方法，贴代码纪念一下。 做法很像筛法

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cstdlib>
 5 #include <cmath>
 6 #include <algorithm>
 7 #include <string>
 8 #include <queue>
 9 #include <stack>
10 #include <vector>
11 #include <map>
12 #include <set>
13 #include <functional>
14 #include <time.h>
15 
16 using namespace std;
17 
18 const int INF = 1<<30;
19 const int MAXN = (int) 1e6+5;
20 
21 int a[MAXN];
22 
23 inline int myAbs(int x) {
24     return x>0 ? x : -x;
25 }
26 
27 int main() {
28     #ifdef Phantom01
29         freopen("HNU12876.in", "r", stdin);
30     #endif //Phantom01
31 
32     memset(a, 0, sizeof(a));
33     for (int i = 1; i < MAXN; i++)
34         for (int j = i<<1; j < MAXN; j += i)
35             a[j]+=i;
36     for (int i = 1; i < MAXN; i++)
37         a[i] = myAbs(a[i]-i);
38 
39     int l, r, k;
40     int T = 1;
41     while (scanf("%d%d%d", &l, &r, &k)!=EOF) {
42         if (l==r&&r==k&&k==0) break;
43         printf("Test %d: ", T++);
44         int ans = 0;
45         for (int i = l; i <= r; i++)
46             if (a[i]<=k)
47                 ans++;
48         printf("%d\n", ans);
49     }
50 
51     return 0;
52 }
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posted @ 2014-08-10 09:43  Phantom01  阅读(219)  评论(0)  编辑  收藏  举报