USACO 4.2 Cowcycles(DFS)

使劲水啊。。。数据量太唬人了。。普通DFS就能过。。。看懂题意就好。。看不懂题是硬伤啊。。

  1 /*

  2 ID: cuizhe

  3 LANG: C++

  4 TASK: cowcycle

  5 */

  6 #include <cstdio>

  7 #include <cstring>

  8 #include <cmath>

  9 #include <string>

 10 #include <ctime>

 11 #include <queue>

 12 #include <vector>

 13 #include <algorithm>

 14 using namespace std;

 15 int o1[101],o2[101],ax[15],ay[15];

 16 double arry[101],d[101];

 17 int x,y,x2,y2,n,m;

 18 double minz = 100000000;

 19 void dfs2(int str,int step)

 20 {

 21     int i,j,num = 0;

 22     double ans = 0,sum = 0;

 23     if(step > m)

 24     {

 25         if(o1[n]*o2[m] >= 3*o1[1]*o2[1])

 26         {

 27 

 28             for(i = 1;i <= n;i ++)

 29             {

 30                 for(j = 1;j <= m;j ++)

 31                 {

 32                     arry[num++] = (o1[i]*1.0/o2[j]);

 33                 }

 34             }

 35             sort(arry,arry+num);

 36             for(i = 0;i < num-1;i ++)

 37             {

 38                 d[i] = arry[i+1] - arry[i];

 39                 sum += d[i];

 40             }

 41             sum = sum/(num-1);

 42             for(i = 0;i < num-1;i ++)

 43             {

 44                 ans += (d[i]-sum)*(d[i]-sum);

 45             }

 46             ans = ans/(num-1);

 47             if(minz > ans)

 48             {

 49                 minz = ans;

 50                 for(i = 1;i <= n;i ++)

 51                 ax[i] = o1[i];

 52                 for(i = 1;i <= m;i ++)

 53                 ay[i] = o2[i];

 54             }

 55         }

 56         return ;

 57     }

 58     for(i = str;i <= y2;i ++)

 59     {

 60         o2[step] = i;

 61         dfs2(i+1,step+1);

 62     }

 63 }

 64 void dfs1(int str,int step)

 65 {

 66     int i;

 67     if(step > n)

 68     {

 69         dfs2(x2,1);

 70         return;

 71     }

 72     for(i = str;i <= y;i ++)

 73     {

 74         o1[step] = i;

 75         dfs1(i+1,step+1);

 76     }

 77     return ;

 78 }

 79 int main()

 80 {

 81     int i;

 82     freopen("cowcycle.in","r",stdin);

 83     freopen("cowcycle.out","w",stdout);

 84     scanf("%d%d",&n,&m);

 85     scanf("%d%d%d%d",&x,&y,&x2,&y2);

 86     dfs1(x,1);

 87     for(i = 1;i <= n;i ++)

 88     {

 89         if(i == 1)

 90         printf("%d",ax[i]);

 91         else

 92         printf(" %d",ax[i]);

 93     }

 94     printf("\n");

 95     for(i = 1;i <= m;i ++)

 96     {

 97         if(i == 1)

 98         printf("%d",ay[i]);

 99         else

100         printf(" %d",ay[i]);

101     }

102     printf("\n");

103     return 0;

104 }