USACO 1.4 clocks

最新推荐文章于 2025-09-07 21:00:40 发布

转载最新推荐文章于 2025-09-07 21:00:40 发布 · 59 阅读

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原文链接：http://www.cnblogs.com/huanyan/archive/2011/05/02/USACO_clocks.html

文章标签：

#c/c++

本文提供了一种解决USACO编程竞赛中Clocks问题的方法。通过使用C++实现的广度优先搜索算法，文章详细展示了如何找到使九个不同步时钟同步所需的最小步骤数。代码中包括了状态表示、队列操作及状态检查等关键部分。

1 /*
2 ID: jiafeim1
3 PROG: clocks
4 LANG: C++
5 */
6 #include < iostream >
7 #include < fstream >
8 #include < algorithm >
9 #include < queue >
10
11 using namespace std;
12
13
14 int ward[ 9 ][ 9 ] = {
15 { 1 , 1 , 0 , 1 , 1 , 0 , 0 , 0 , 0 },
16 { 1 , 1 , 1 , 0 , 0 , 0 , 0 , 0 , 0 },
17 { 0 , 1 , 1 , 0 , 1 , 1 , 0 , 0 , 0 },
18 { 1 , 0 , 0 , 1 , 0 , 0 , 1 , 0 , 0 },
19 { 0 , 1 , 0 , 1 , 1 , 1 , 0 , 1 , 0 },
20 { 0 , 0 , 1 , 0 , 0 , 1 , 0 , 0 , 1 },
21 { 0 , 0 , 0 , 1 , 1 , 0 , 1 , 1 , 0 },
22 { 0 , 0 , 0 , 0 , 0 , 0 , 1 , 1 , 1 },
23 { 0 , 0 , 0 , 0 , 1 , 1 , 0 , 1 , 1 }
24 };
25
26 int rank[ 9 ] = { 1 , 4 , 16 , 64 , 256 , 1024 , 4096 , 16384 , 65536 };
27 bool haveDo[ 262144 ] = { false };
28 struct work
29 {
30 long clock_state;
31 long step_state;
32 work( long clock, long step)
33 {
34 clock_state = clock;
35 step_state = step;
36 }
37 work(){}
38 };
39 std::queue < work > wq;
40 int main()
41 {
42 ofstream fout ( " clocks.out " );
43 ifstream fin ( " clocks.in " );
44 long start_state = 0 ;
45 long temp;
46 for ( int i = 0 ; i != 9 ; ++ i)
47 {
48 fin >> temp;
49 temp /= 3 ;
50 temp %= 4 ;
51 start_state = start_state * 4 + temp;
52 }
53 wq.push(work(start_state, 0 ));
54 haveDo[ 0 ] = true ;
55 work now;
56 long res = 0 ;
57 while ( ! wq.empty())
58 {
59 now = wq.front();
60 wq.pop();
61 if (now.clock_state == 0 )
62 {
63 res = now.step_state;
64 break ;
65 }
66 if (now.step_state == 262143 ) continue ;
67 for ( int i = 0 ;i != 9 ; ++ i)
68 {
69 long temp_step = now.step_state;
70 temp_step = (temp_step / rank[i]) % 4 ;
71 if (temp_step == 3 ) continue ;
72 temp_step = now.step_state + rank[i];
73
74 if (haveDo[temp_step]) continue ;
75 else
76 {
77 haveDo[temp_step] = true ;
78 long temp_clock = now.clock_state;
79 for ( int j = 0 ;j != 9 ; ++ j)
80 {
81 if (ward[i][j] == 0 ) continue ;
82 long js = (temp_clock / rank[ 8 - j]) % 4 ;
83 if (js == 3 )
84 {
85 temp_clock -= 3 * rank[ 8 - j];
86 }
87 else
88 {
89
90 temp_clock += rank[ 8 - j];
91 }
92
93 }
94 wq.push(work(temp_clock,temp_step));
95 }
96
97 }
98 }
99
100 bool space = false ;
101 for ( int i = 0 ;i != 9 && res != 0 ; ++ i)
102 {
103 long l = res % 4 ;
104 res /= 4 ;
105 for ( int j = 0 ;j != l; ++ j)
106 {
107 if (space) fout << " " ;
108 fout << i + 1 ;
109 space = true ;
110 }
111 }
112 fout << endl;
113 fin.close();
114 fout.close();
115 return 0 ;
116 }

转载于:https://www.cnblogs.com/huanyan/archive/2011/05/02/USACO_clocks.html