hdu 刷题记录

矫情吗；* 2022-03-31 09:58 246阅读 0赞

1007 最近点对问题，采用分治法策略搞定

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

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 }

1008 沙茶题，水题预警

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

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 }

1009 贪心排序乱搞一波

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

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 }

2710 机智的离线打表

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

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 }

[ContractedBlock.gif]: https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif
[ExpandedBlockStart.gif]: /images/20220331/7bcf38735e5649489b86d923866ce81d.png