1 #include <iostream>
 2
 3 using namespace std;
 4
 5 int mouse(int n)
 6 {
 7     if (0 == n)
 8     {
 9         return 1;
10     }
11     else if (1 == n)
12     {
13         return 1;
14     }
15     else if (2 == n)
16     {
17         return 2;
18     }
19     else
20     {
21         return mouse(n-2)+mouse(n-3);
22     }
23 }
24
25 int main()
26 {
27     int n;
28
29     while (cin >> n)
30     {
31         cout << mouse(n) << endl;
32     }
33
34     return 0;
35 }

 1 #include <iostream>
 2
 3  using namespace std;
 4
 5  int num(int);
 6
 7  int main()
 8  {
 9      int n;
10      while (cin >> n)
11      {
12          cout << "The answer is " << num(n) << endl;
13      }
14
15
16      return 0;
17  }
18
19  int num(int n)
20  {
21      int a[3] = {1, 0, 0};
22      int t1, t2;
23
24      for (int i=0; i<n; ++i)
25      {
26          t1 = a[1];
27          t2 = a[2];
28          a[1] = a[0];
29          a[2] = t1;
30          a[0] = t1 + t2;
31
32          cout << i+1 << " has " << (a[0]+a[1]+a[2]) << " mice" << endl;
33      }
34      return (a[0]+a[1]+a[2]);
35  }

 1 #include <iostream>
 2 #include <cstring>
 3
 4 const int MAX = 100000;
 5
 6 using namespace std;
 7
 8 void add(char *str1, char *str2, char *str3);
 9 void num(int, char *);
10
11 int main()
12 {
13     int n;
14     char s[MAX];
15
16     while (cin >> n)
17     {
18         num(n, s);
19         cout << "The answer is " << s << endl;
20     }
21
22
23     return 0;
24 }
25
26 void num(int n, char *s)
27 {
28     //Big Int
29     char a0[MAX];
30     char a1[MAX];
31     char a2[MAX];
32     char t1[MAX];
33     char t2[MAX];
34
35     strcpy(a0, "1");
36     strcpy(a1, "0");
37     strcpy(a2, "0");
38
39     for (int i=0; i<n; ++i)
40     {
41         strcpy(t1, a1);
42         strcpy(t2, a2);
43         strcpy(a1, a0);
44         strcpy(a2, t1);
45         add(t1, t2, a0);
46     }
47     char temp1[MAX];
48     char temp2[MAX];
49     char temp3[MAX];
50     strcpy(temp1, a0);
51     add(temp1, a1, temp2);
52     add(temp2, a2, temp3);
53     strcpy(s, temp3);
54 }
55
56 void add(char *str1, char *str2, char *str3)
57 {
58     int i, j, i1, i2, tmp, carry;
59     int len1 = strlen(str1);
60     int len2 = strlen(str2);
61     char ch;
62
63     i1 = len1 - 1;
64     i2 = len2 - 1;
65     j = carry = 0;
66
67     for ( ; i1>=0 && i2>=0; ++j, --i1, --i2)
68     {
69         tmp = str1[i1] - '0' + str2[i2] - '0' + carry;
70         carry = tmp / 10;
71         str3[j] = tmp % 10 + '0';
72     }
73     while (i1 >= 0)
74     {
75         tmp = str1[i1--] - '0' + carry;
76         carry = tmp/10;
77         str3[j++] = tmp%10 + '0';
78     }
79     while (i2 >= 0)
80     {
81         tmp = str2[i2--] -'0' + carry;
82         carry = tmp/10;
83         str3[j++] = tmp%10 + '0';
84     }
85
86     if (carry)
87     {
88         str3[j++] = carry + '0';
89     }
90     str3[j] = '\0';
91
92     for (i=0, --j; i<j; ++i, --j)
93     {
94         ch = str3[i];
95         str3[i] = str3[j];
96         str3[j] = ch;
97     }
98 }