poj3334Connected Gheeves(二分）

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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

  1 #include <iostream>

  2 #include<cstdio>

  3 #include<cstring>

  4 #include<algorithm>

  5 #include<stdlib.h>

  6 #include<vector>

  7 #include<cmath>

  8 #include<queue>

  9 #include<set>

 10 using namespace std;

 11 #define N 2010

 12 #define LL long long

 13 #define INF 0xfffffff

 14 const double eps = 1e-8;

 15 const double pi = acos(-1.0);

 16 const double inf = ~0u>>2;

 17 struct point

 18 {

 19     double x ,y;

 20     point(double x=0,double y=0):x(x),y(y){}

 21 }p[N],q[N],ch[N];

 22 double minz;

 23 int n,m;

 24 typedef point pointt;

 25 pointt operator -(point a,point b)

 26 {

 27     return point(a.x-b.x,a.y-b.y);

 28 }

 29 int dcmp(double x)

 30 {

 31     if(fabs(x)<eps) return 0;

 32     return x<0?-1:1;

 33 }

 34 double dis(point a)

 35 {

 36     return sqrt(a.x*a.x+a.y*a.y);

 37 }

 38 double cross(point a,point b)

 39 {

 40     return a.x*b.y-a.y*b.x;

 41 }

 42 double getarea(int n,point p[])

 43 {

 44     int i;

 45     double s = 0;

 46     for(i = 2; i < n ; i++)

 47     s+=cross(p[i]-p[1],p[i+1]-p[1]);

 48     return s/2;

 49 }

 50 double cal(double r,point p[],int n)

 51 {

 52     int i,j;

 53     int k = 1;

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

 55     if(p[i].y<p[k].y)    k = i;

 56 

 57     if(dcmp(r-p[k].y)<=0) return 0.0;

 58 

 59     point p1,p2;

 60     int g = 0;

 61     for(i = 1; i < k; i++)

 62     if(dcmp(p[i].y-r)>=0&&dcmp(p[i+1].y-r)<0)

 63     {

 64         p1.y = r;

 65         double d = r-p[i+1].y;

 66         p1.x = d*(p[i].x-p[i+1].x)/(p[i].y-p[i+1].y)+p[i+1].x;

 67         break;

 68     }

 69 

 70     for(j = k ; j >= i+1; j--)

 71     ch[++g] = p[j];

 72     ch[++g] = p1;

 73     for(i = k+1 ; i <= n; i++)

 74     if(dcmp(p[i-1].y-r)<0&&dcmp(p[i].y-r)>=0)

 75     {

 76         p2.y = r;

 77         double d = r-p[i-1].y;

 78         p2.x = d*(p[i].x-p[i-1].x)/(p[i].y-p[i-1].y)+p[i-1].x;

 79         break;

 80     }

 81     ch[++g] = p2;

 82     for(j = i-1 ; j > k; j--)

 83     ch[++g] = p[j];

 84 

 85     return fabs(getarea(g,ch));

 86 }

 87 int main()

 88 {

 89     int t,i,a;

 90     cin>>t;

 91     while(t--)

 92     {

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

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

 95         minz = INF;

 96         double maxz  = INF;

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

 98         {

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

100             maxz = min(maxz,p[i].y);

101         }

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

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

104         {

105             scanf("%lf%lf",&q[i].x,&q[i].y);

106             maxz = min(maxz,p[i].y);

107         }

108         minz = min(min(p[1].y,p[n].y),min(q[1].y,q[m].y));

109         double lef = maxz,rig = minz,mid;

110         while(fabs(rig-lef)>eps)

111         {

112             mid = (rig+lef)/2.0;

113             double s1 = cal(mid,p,n),s2 = cal(mid,q,m);

114             if(dcmp(s1+s2-a)>0)

115             rig = mid;

116             else lef = mid;

117         }

118         printf("%.3f\n",lef);

119     }

120     return 0;

121 }

View Code

感觉不错的别人的代码

  1 #include <iostream>

  2 #include<cstdio>

  3 #include<cstring>

  4 #include<algorithm>

  5 #include<stdlib.h>

  6 #include<vector>

  7 #include<cmath>

  8 #include<queue>

  9 #include<set>

 10 using namespace std;

 11 #define N 2010

 12 #define LL long long

 13 #define INF 0xfffffff

 14 const double eps = 1e-8;

 15 const double pi = acos(-1.0);

 16 const double inf = ~0u>>2;

 17 struct point

 18 {

 19     double x ,y;

 20     point(double x=0,double y=0):x(x),y(y){}

 21 }p[N],q[N],ch[N];

 22 double minz;

 23 typedef point pointt;

 24 pointt operator -(point a,point b)

 25 {

 26     return point(a.x-b.x,a.y-b.y);

 27 }

 28 int dcmp(double x)

 29 {

 30     if(fabs(x)<eps) return 0;

 31     return x<0?-1:1;

 32 }

 33 double dis(point a)

 34 {

 35     return sqrt(a.x*a.x+a.y*a.y);

 36 }

 37 double cross(point a,point b)

 38 {

 39     return a.x*b.y-a.y*b.x;

 40 }

 41 

 42 double getarea(int n,point p[])

 43 {

 44     int i;

 45     double s = 0;

 46     for(i = 1; i < n-1 ; i++)

 47     s+=cross(p[i]-p[0],p[i+1]-p[0]);

 48     return s/2;

 49 }

 50 //double cal(double r,point p[],int n)

 51 //{

 52 //    int i,j;

 53 //    int k = 1;

 54 //    for(i = 1; i <= n; i++)

 55 //    if(p[i].y<p[k].y)    k = i;

 56 //

 57 //    r = min(r,minz);

 58 //    if(dcmp(r-p[k].y)<=0) return 0.0;

 59 //

 60 //    point p1,p2;

 61 //    int g = 0;

 62 //    for(i = 1; i < k; i++)

 63 //    if(dcmp(p[i].y-r)>=0&&dcmp(p[i+1].y-r)<0)

 64 //    {

 65 //        p1.y = r;

 66 //        double d = r-p[i+1].y;

 67 //        p1.x = d*(p[i].x-p[i+1].x)/(p[i].y-p[i+1].y)+p[i+1].x;

 68 //        break;

 69 //    }

 70 //   // cout<<p1.x<<" "<<p1.y<<endl;

 71 //    for(j = k ; j >= i+1; j--)

 72 //    ch[++g] = p[j];

 73 //    ch[++g] = p1;

 74 //    for(i = k+1 ; i <= n; i++)

 75 //    if(dcmp(p[i-1].y-r)<0&&dcmp(p[i].y-r)>=0)

 76 //    {

 77 //        p2.y = r;

 78 //        double d = r-p[i-1].y;

 79 //        p2.x = d*(p[i].x-p[i-1].x)/(p[i].y-p[i-1].y)+p[i-1].x;

 80 //        break;

 81 //    }

 82 //    ch[++g] = p2;

 83 //    for(j = i-1 ; j > k; j--)

 84 //    ch[++g] = p[j];

 85 //

 86 //    return fabs(getarea(g,ch));

 87 //}

 88 point intersect(point p1,point p2,point p3,point p4){

 89     point p;

 90     double a1,b1,a2,b2,c1,c2,d;

 91     a1=p1.y-p2.y; b1=p2.x-p1.x; c1=p1.x*p2.y-p2.x*p1.y;

 92     a2=p3.y-p4.y; b2=p4.x-p3.x; c2=p3.x*p4.x-p4.x*p3.y;

 93     d=a1*b2-a2*b1;

 94     p.x=(-c1*b2+c2*b1)/d;

 95     p.y=(-a1*c2+a2*c1)/d;

 96     return p;

 97 }

 98 bool pan(point a,point b,double y){

 99     return dcmp(a.y-y)*dcmp(b.y-y)<=0;

100 }

101 double cal(double y,point P[],int n){

102 

103     int i,j,k;

104    int tot=0;

105     point a=point(0,y),b=point(1,y);

106     for(i=1;i<n;i++){

107         if(pan(P[i],P[i+1],y)){

108             ch[tot++]=intersect(P[i],P[i+1],a,b);

109             break;

110         }

111     }

112     for(j=i+1;j<n;j++){

113         ch[tot++]=P[j];

114         if(pan(P[j],P[j+1],y)){

115             ch[tot++]=intersect(P[j],P[j+1],a,b);

116             break;

117         }

118     }

119     double area=getarea(tot,ch);

120     return area;

121 }

122 int main()

123 {

124     int t,i,a,n,m;

125     cin>>t;

126     while(t--)

127     {

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

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

130         minz = INF;

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

132         {

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

134             minz = min(minz,p[i].y);

135         }

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

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

138         {

139             scanf("%lf%lf",&q[i].x,&q[i].y);

140             minz = min(minz,q[i].y);

141         }

142         double maxz = min(min(p[1].y,p[n].y),min(q[1].y,q[m].y));

143         double lef = minz,rig = maxz,mid;

144         while(fabs(rig-lef)>eps)

145         {

146             mid = (rig+lef)/2.0;

147             double s1 = cal(mid,p,n),s2 = cal(mid,q,m);

148             if(dcmp(s1+s2-a)>0)

149             rig = mid;

150             else lef = mid;

151         }

152         printf("%.3f\n",lef);

153     }

154     return 0;

155 }

View Code