Sicily-1152 回溯算法

一．题意：

走日字，每个位置都有有8种新位置，从起点开始刚好过29步遍历其他位置一遍。

二．代码

 1 //

 2 //  main.cpp

 3 //  Sicily-1152 回溯算法

 4 //

 5 //  Created by ashley on 14-10-21.

 6 //  Copyright (c) 2014年 ashley. All rights reserved.

 7 //

 8 

 9 #include <iostream>

10 #include <utility>

11 using namespace std;

12 

13 //pair<int, int> moves[8] = {(1, 2), (2, 1), (2, -1), (1, -2), (-1, -2), (-2, -1), (-2, 1), (-1, 2)};

14 int moveX[8] = {1, 2, 2, 1, -1, -2, -2, -1};

15 int moveY[8] = {2, 1, -1, -2, -2, -1, 1, 2};

16 bool isVisited[30];

17 int path[30];

18 int counter;

19 bool success;

20 typedef struct

21 {

22     int x;

23     int y;

24 }point;

25 void dfs(point startPoint)

26 {

27     if (counter == 30) {

28         success = true;

29         cout << path[0];

30         for (int i = 1; i < 30; i++) {

31             cout << " " << path[i];

32         }

33         cout << endl;

34         return;

35     }

36     for (int i = 0; i < 8; i++) {

37         point nextPoint = {startPoint.x + moveX[i], startPoint.y + moveY[i]};

38         int num = nextPoint.y * 6 + nextPoint.x + 1;

39         if (nextPoint.x < 6 && nextPoint.x >= 0 && nextPoint.y < 5 && nextPoint.y >= 0 && isVisited[num - 1] == false) {

40             isVisited[num - 1] = true;

41             path[counter] = num;

42             counter++;

43             if (success) {

44                 return;

45             }

46             dfs(nextPoint);

47             isVisited[num - 1] = false;

48             counter--;

49         }

50     }

51 }

52 int main(int argc, const char * argv[])

53 {

54     int source;

55     while (cin >> source) {

56         if (source == -1) {

57             break;

58         }

59         point sourcePoint = {source % 6 - 1, source / 6};

60         for (int i = 0; i < 30; i++) {

61             isVisited[i] = false;

62         }

63         success = false;

64         counter = 1;

65         //源点只能走一次

66         isVisited[source - 1] = true;

67         path[counter - 1] = source;

68         dfs(sourcePoint);

69     }

70     return 0;

71 }