poj3334Connected Gheeves(二分）

链接

二分高度，算面积的地方有点麻烦，没有用求交点的模板，直接自己按三角形相似手算了一下，写的有点麻烦。

上下界直接取水可放的最高点以及最低点。

自己的长得很挫的代码

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<cmath>
 #include<queue>
 #include<set>
 using namespace std;
 #define N 2010
 #define LL long long
 #define INF 0xfffffff
 const double eps = 1e-;
 const double pi = acos(-1.0);
 const double inf = ~0u>>;
 struct point
 {
     double x ,y;
     point(double x=,double y=):x(x),y(y){}
 }p[N],q[N],ch[N];
 double minz;
 int n,m;
 typedef point pointt;
 pointt operator -(point a,point b)
 {
     return point(a.x-b.x,a.y-b.y);
 }
 int dcmp(double x)
 {
     if(fabs(x)<eps) return ;
     return x<?-:;
 }
 double dis(point a)
 {
     return sqrt(a.x*a.x+a.y*a.y);
 }
 double cross(point a,point b)
 {
     return a.x*b.y-a.y*b.x;
 }
 double getarea(int n,point p[])
 {
     int i;
     double s = ;
     for(i = ; i < n ; i++)
     s+=cross(p[i]-p[],p[i+]-p[]);
     return s/;
 }
 double cal(double r,point p[],int n)
 {
     int i,j;
     int k = ;
     for(i = ; i <= n; i++)
     if(p[i].y<p[k].y)    k = i;

     if(dcmp(r-p[k].y)<=) return 0.0;

     point p1,p2;
     int g = ;
     for(i = ; i < k; i++)
     if(dcmp(p[i].y-r)>=&&dcmp(p[i+].y-r)<)
     {
         p1.y = r;
         double d = r-p[i+].y;
         p1.x = d*(p[i].x-p[i+].x)/(p[i].y-p[i+].y)+p[i+].x;
         break;
     }

     for(j = k ; j >= i+; j--)
     ch[++g] = p[j];
     ch[++g] = p1;
     for(i = k+ ; i <= n; i++)
     if(dcmp(p[i-].y-r)<&&dcmp(p[i].y-r)>=)
     {
         p2.y = r;
         double d = r-p[i-].y;
         p2.x = d*(p[i].x-p[i-].x)/(p[i].y-p[i-].y)+p[i-].x;
         break;
     }
     ch[++g] = p2;
     for(j = i- ; j > k; j--)
     ch[++g] = p[j];

     return fabs(getarea(g,ch));
 }
 int main()
 {
     int t,i,a;
     cin>>t;
     while(t--)
     {
         scanf("%d",&a);
         scanf("%d",&n);
         minz = INF;
         double maxz  = INF;
         for(i = ; i <= n ;i++)
         {
             scanf("%lf%lf",&p[i].x,&p[i].y);
             maxz = min(maxz,p[i].y);
         }
         scanf("%d",&m);
         for(i = ; i <= m ;i++)
         {
             scanf("%lf%lf",&q[i].x,&q[i].y);
             maxz = min(maxz,p[i].y);
         }
         minz = min(min(p[].y,p[n].y),min(q[].y,q[m].y));
         double lef = maxz,rig = minz,mid;
         while(fabs(rig-lef)>eps)
         {
             mid = (rig+lef)/2.0;
             double s1 = cal(mid,p,n),s2 = cal(mid,q,m);
             if(dcmp(s1+s2-a)>)
             rig = mid;
             else lef = mid;
         }
         printf("%.3f\n",lef);
     }
     return ;
 }

感觉不错的别人的代码

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 #include<vector>
 #include<cmath>
 #include<queue>
 #include<set>
 using namespace std;
 #define N 2010
 #define LL long long
 #define INF 0xfffffff
 const double eps = 1e-;
 const double pi = acos(-1.0);
 const double inf = ~0u>>;
 struct point
 {
     double x ,y;
     point(double x=,double y=):x(x),y(y){}
 }p[N],q[N],ch[N];
 double minz;
 typedef point pointt;
 pointt operator -(point a,point b)
 {
     return point(a.x-b.x,a.y-b.y);
 }
 int dcmp(double x)
 {
     if(fabs(x)<eps) return ;
     return x<?-:;
 }
 double dis(point a)
 {
     return sqrt(a.x*a.x+a.y*a.y);
 }
 double cross(point a,point b)
 {
     return a.x*b.y-a.y*b.x;
 }

 double getarea(int n,point p[])
 {
     int i;
     double s = ;
     for(i = ; i < n- ; i++)
     s+=cross(p[i]-p[],p[i+]-p[]);
     return s/;
 }
 //double cal(double r,point p[],int n)
 //{
 //    int i,j;
 //    int k = 1;
 //    for(i = 1; i <= n; i++)
 //    if(p[i].y<p[k].y)    k = i;
 //
 //    r = min(r,minz);
 //    if(dcmp(r-p[k].y)<=0) return 0.0;
 //
 //    point p1,p2;
 //    int g = 0;
 //    for(i = 1; i < k; i++)
 //    if(dcmp(p[i].y-r)>=0&&dcmp(p[i+1].y-r)<0)
 //    {
 //        p1.y = r;
 //        double d = r-p[i+1].y;
 //        p1.x = d*(p[i].x-p[i+1].x)/(p[i].y-p[i+1].y)+p[i+1].x;
 //        break;
 //    }
 //   // cout<<p1.x<<" "<<p1.y<<endl;
 //    for(j = k ; j >= i+1; j--)
 //    ch[++g] = p[j];
 //    ch[++g] = p1;
 //    for(i = k+1 ; i <= n; i++)
 //    if(dcmp(p[i-1].y-r)<0&&dcmp(p[i].y-r)>=0)
 //    {
 //        p2.y = r;
 //        double d = r-p[i-1].y;
 //        p2.x = d*(p[i].x-p[i-1].x)/(p[i].y-p[i-1].y)+p[i-1].x;
 //        break;
 //    }
 //    ch[++g] = p2;
 //    for(j = i-1 ; j > k; j--)
 //    ch[++g] = p[j];
 //
 //    return fabs(getarea(g,ch));
 //}
 point intersect(point p1,point p2,point p3,point p4){
     point p;
     double a1,b1,a2,b2,c1,c2,d;
     a1=p1.y-p2.y; b1=p2.x-p1.x; c1=p1.x*p2.y-p2.x*p1.y;
     a2=p3.y-p4.y; b2=p4.x-p3.x; c2=p3.x*p4.x-p4.x*p3.y;
     d=a1*b2-a2*b1;
     p.x=(-c1*b2+c2*b1)/d;
     p.y=(-a1*c2+a2*c1)/d;
     return p;
 }
 bool pan(point a,point b,double y){
     return dcmp(a.y-y)*dcmp(b.y-y)<=;
 }
 double cal(double y,point P[],int n){

     int i,j,k;
    int tot=;
     point a=point(,y),b=point(,y);
     for(i=;i<n;i++){
         if(pan(P[i],P[i+],y)){
             ch[tot++]=intersect(P[i],P[i+],a,b);
             break;
         }
     }
     for(j=i+;j<n;j++){
         ch[tot++]=P[j];
         if(pan(P[j],P[j+],y)){
             ch[tot++]=intersect(P[j],P[j+],a,b);
             break;
         }
     }
     double area=getarea(tot,ch);
     return area;
 }
 int main()
 {
     int t,i,a,n,m;
     cin>>t;
     while(t--)
     {
         scanf("%d",&a);
         scanf("%d",&n);
         minz = INF;
         for(i = ; i <= n ;i++)
         {
             scanf("%lf%lf",&p[i].x,&p[i].y);
             minz = min(minz,p[i].y);
         }
         scanf("%d",&m);
         for(i = ; i <= m ;i++)
         {
             scanf("%lf%lf",&q[i].x,&q[i].y);
             minz = min(minz,q[i].y);
         }
         double maxz = min(min(p[].y,p[n].y),min(q[].y,q[m].y));
         double lef = minz,rig = maxz,mid;
         while(fabs(rig-lef)>eps)
         {
             mid = (rig+lef)/2.0;
             double s1 = cal(mid,p,n),s2 = cal(mid,q,m);
             if(dcmp(s1+s2-a)>)
             rig = mid;
             else lef = mid;
         }
         printf("%.3f\n",lef);
     }
     return ;
 }