hdu 刷题记录

1007 最近点对问题，采用分治法策略搞定

 1 #include<iostream>

 2 #include<cmath>

 3 #include<algorithm>

 4 using namespace std;

 5 int n;

 6 struct node

 7 {

 8   double x;

 9   double y;

10 }p[100005];

11 int a[100005];

12 double cmpx(node a,node b)

13 {

14   return a.x<b.x;

15 }

16 double cmpy(int a,int b)

17 {

18   return p[a].y<p[b].y;

19 }

20 double min(double a,double b)

21 {

22   return a<b?a:b;

23 }

24 double dis(node a,node b)

25 {

26   return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));

27 }

28 double find(int l,int r)

29 {

30      if(r==l+1)

31       return dis(p[l],p[r]);

32      if(l+2==r)

33       return min(dis(p[l],p[r]),min(dis(p[l],p[l+1]),dis(p[l+1],p[r])));

34      int mid=(l+r)>>1;

35      double ans=min(find(l,mid),find(mid+1,r));

36      int i,j,cnt=0;

37      for(i=l;i<=r;i++)

38      {

39        if(p[i].x>=p[mid].x-ans&&p[i].x<=p[mid].x+ans)

40           a[cnt++]=i;

41      }

42      sort(a,a+cnt,cmpy);

43      for(i=0;i<cnt;i++)

44      {

45        for(j=i+1;j<cnt;j++)

46        {

47          if(p[a[j]].y-p[a[i]].y>=ans) break;

48          ans=min(ans,dis(p[a[i]],p[a[j]]));

49        }

50      } 

51      return ans;

52 }

53 int main()

54 {

55     int i;

56    

57     while(scanf("%d",&n)!=EOF)

58     {

59       if(!n) break;

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

61        scanf("%lf %lf",&p[i].x,&p[i].y);

62       sort(p,p+n,cmpx);

63       printf("%.2lf%\n",find(0,n-1)/2);

64     }

65     return 0;

66 }

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1008 沙茶题，水题预警

 1  #include<stdio.h>

 2 int main()

 3 {

 4     int n;

 5     int start,a;

 6     int t;

 7     int i;

 8     while(scanf("%d",&n),n)

 9     {

10         t=0;start=0;

11         for(int i=1;i<=n;i++)

12         {

13             scanf("%d",&a);

14             if(a>start)t+=6*(a-start);

15             else t+=4*(start-a);

16             t+=5;

17             start=a;

18         }

19         printf("%d\n",t);

20     }    

21     return 0; 

22 }

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1009 贪心排序乱搞一波

 1 #include<iostream>

 2 #include<string.h>

 3 #include<stdio.h>

 4 #include<ctype.h>

 5 #include<algorithm>

 6 #include<stack>

 7 #include<queue>

 8 #include<set>

 9 #include<math.h>

10 #include<vector>

11 #include<map>

12 #include<deque>

13 #include<list>

14 using namespace std;

15 typedef struct node{

16     int j;

17     int f;

18     double d;

19 }MC;

20 MC a[1003];

21 bool cmp(MC a,MC b)

22 {

23     return a.d>b.d;

24 }

25 int main()

26 {

27     int n,m,i;

28     double t;

29     while(cin>>n>>m)

30     {

31         if(n==-1&&m==-1)

32             break;

33         for(int i=0;i<m;i++)

34         {

35             cin>>a[i].j>>a[i].f;

36             a[i].d=1.0*a[i].j/a[i].f;

37         }

38         sort(a,a+m,cmp);

39         t=0;

40         for(int i=0;i<m;i++)

41         {

42             if(n>a[i].f)

43             {

44                 t+=a[i].j;

45                 n-=a[i].f;

46             }

47             else

48             {

49                 t+=n*a[i].d;break;

50             }

51         }

52         printf("%.3lf\n",t);

53     }

54     return 0;

55 }

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2710 机智的离线打表

 1 #include<iostream>

 2 #include<string.h>

 3 #include<stdio.h>

 4 #include<ctype.h>

 5 #include<algorithm>

 6 #include<stack>

 7 #include<queue>

 8 #include<set>

 9 #include<math.h>

10 #include<vector>

11 #include<map>

12 #include<deque>

13 #include<list>

14 using namespace std;

15 int a[20010]={0,1};

16 int main()

17 {

18     for(int i=2;i<=20000;i++)

19     {

20         if(a[i]==0)

21         {

22             for(int j=i;j<=20000;j+=i)

23                 a[j]=i;

24         }

25     }

26     int n;

27     while(scanf("%d",&n)!=EOF)

28     {

29         int ans;

30         int maxn=0;

31         while(n--)

32         {

33             int m;

34             scanf("%d",&m);

35             if(a[m]>maxn)

36             {

37                 ans=m;

38                 maxn=a[m];

39             }

40         }

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

42     }

43     return 0;

44 }

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