HDU 1104Remainder

 1 #include<cstdio>

 2 #include<iostream>

 3 #include<queue>

 4 #include<cstring>

 5 using namespace std;

 6 #define MAXN 1000010

 7 int c[MAXN];

 8 int fa[MAXN];

 9 int vis[MAXN];

10 int s[MAXN];

11 char op[5] = "+-*%";

12 

13 int mod(int a, int b) {

14     return ( a % b + b) % b;

15 }

16 

17 int main() {

18     int des, n, k, m, next, now, mo, cnt;

19     while (scanf("%d%d%d", &n, &k, &m) != EOF && k) {

20         mo = m*k;

21         queue <int> q;

22         des = mod(n + 1, k);

23         n = mod(n, mo);

24         memset(vis, 0, sizeof (vis));

25         q.push(n);

26         vis[n] = 1;

27         fa[n] = -1;

28         c[n] = -1;

29         while (!q.empty()) {

30             now = q.front();

31             q.pop();

32             for (int i = 0; i < 4; ++i) {

33                 if (i == 0)next = (now + m) % mo;

34                 else if (i == 1)next = mod(now - m, mo);

35                 else if (i == 2)next = now * m % mo;

36                 else next = now % m;

37                 if (!vis[next]) {

38                     vis[next] = 1;

39                     fa[next] = now;

40                     c[next] = i;

41                     if (next % k == des)

42                         goto L;

43                     q.push(next);

44                 }

45             }

46         }

47         printf("0\n");

48         continue;

49 L:

50         cnt = 0;

51         while (fa[next] >= 0) {

52             s[cnt++] = c[next];

53             next = fa[next];

54         }

55         printf("%d\n", cnt);

56         while (cnt)

57             printf("%c", op[s[--cnt]]);

58         printf("\n");

59 

60     }

61     return 0;

62 }

代码搬运工

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还有数论的知识。