【HDOJ】5179 beautiful number

DFS。

 1 /* 5179 */
 2 #include <iostream>
 3 #include <algorithm>
 4 #include <map>
 5 #include <cstdio>
 6 #include <cstring>
 7 using namespace std;
 8
 9 #define MAXN 1500
10
11 map<int, bool> tb;
12 int a[MAXN], n, v;
13 int buf[7][5] = {
14     {1,1},
15     {3,6,2,1}, {4,8,4,2,1},
16     {3,6,3,1}, {3,9,3,1},
17     {2,5,1},
18     {2,7,1}
19 };
20
21 void dfs(int beg, int len, int val) {
22     int i, k, tmp = 10*val;
23     if (len >= 10)
24         return ;
25     for (i=beg; i<=buf[v][0]; ++i) {
26         k = tmp + buf[v][i];
27         if (!tb[k]) {
28             tb[k] = true;
29             a[n++] = k;
30         }
31         dfs(i, len+1, k);
32     }
33 }
34
35 void init() {
36     int i, j, k;
37
38     n = 0;
39     for (v=0; v<7; ++v)
40         dfs(1, 1, 0);
41     sort(a, a+n);
42 }
43
44 int main() {
45     int t, l, r;
46     int i, j, k;
47     int ans;
48
49     #ifndef ONLINE_JUDGE
50         freopen("data.in", "r", stdin);
51         freopen("data.out", "w", stdout);
52     #endif
53
54     init();
55     scanf("%d", &t);
56     while (t--) {
57         scanf("%d %d", &l, &r);
58         ans = 0;
59         for (i=0; i<n; ++i)
60             if (l<=a[i] && r>=a[i])
61                 ++ans;
62         printf("%d\n", ans);
63     }
64
65     return 0;
66 }