POJ 1054 The Troublesome Frog

题目链接

如果跳，那么这条路上所有的点都在图上。搞一个判断就行。写的不好，各种没状态，直接暴力水过。

 1 #include <cstdio>

 2 #include <cstring>

 3 #include <iostream>

 4 #include <cmath>

 5 #include <algorithm>

 6 using namespace std;

 7 struct node

 8 {

 9     int x,y;

10 } p[5001];

11 bool flag[5001][5001];

12 bool cmp(node a,node b)

13 {

14     if(a.x == b.x)

15         return a.y < b.y;

16     else

17         return a.x < b.x;

18 }

19 int main()

20 {

21     int r,c,i,j,n,ans,temp,x,y,tx,ty;

22     memset(flag,0,sizeof(flag));

23     scanf("%d%d",&r,&c);

24     scanf("%d",&n);

25     for(i = 0; i < n; i ++)

26     {

27         scanf("%d%d",&p[i].x,&p[i].y);

28         flag[p[i].x][p[i].y] = 1;

29     }

30     sort(p,p+n,cmp);

31     ans = 2;

32     for(i = 0; i < n; i ++)

33     {

34         for(j = i+1; j < n; j ++)

35         {

36             x = p[j].x - p[i].x;

37             y = p[j].y - p[i].y;

38             tx = p[j].x;

39             ty = p[j].y;

40             if(p[i].x-x <= r&&p[i].x-x >= 1&&p[i].y-y <= c&&p[i].y-y >= 1)

41             continue;

42             for(temp = 2;; temp ++)

43             {

44                 tx = tx+x;

45                 ty = ty+y;

46                 if(tx > r||tx < 1)

47                     break;

48                 if(ty > c||ty < 1)

49                     break;

50                 if(!flag[tx][ty])

51                 {

52                     temp = 0;//注意这里，SB啊。

53                     break;

54                 }

55             }

56             ans = max(ans,temp);

57         }

58     }

59     if(ans < 3)

60     printf("0\n");

61     else

62     printf("%d\n",ans);

63     return 0;

64 }