Wall
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 3449 Accepted Submission(s): 987
a perfect shape and nice tall towers. Instead, he ordered to build the wall around the whole castle using the least amount of stone and labor, but demanded that the wall should not come closer to the castle than a certain distance. If the King finds that the
Architect has used more resources to build the wall than it was absolutely necessary to satisfy those requirements, then the Architect will loose his head. Moreover, he demanded Architect to introduce at once a plan of the wall listing the exact amount of
resources that are needed to build the wall.
Your task is to help poor Architect to save his head, by writing a program that will find the minimum possible length of the wall that he could build around the castle to satisfy King's requirements.
The task is somewhat simplified by the fact, that the King's castle has a polygonal shape and is situated on a flat ground. The Architect has already established a Cartesian coordinate system and has precisely measured the coordinates of all castle's vertices
in feet.
the wall to come close to the castle.
Next N lines describe coordinates of castle's vertices in a clockwise order. Each line contains two integer numbers Xi and Yi separated by a space (-10000 <= Xi, Yi <= 10000) that represent the coordinates of ith vertex. All vertices are different and the sides
of the castle do not intersect anywhere except for vertices.
because the floating numbers are not invented yet. However, you must round the result in such a way, that it is accurate to 8 inches (1 foot is equal to 12 inches), since the King will not tolerate larger error in the estimates.
This problem contains multiple test cases!
The first line of a multiple input is an integer N, then a blank line followed by N input blocks. Each input block is in the format indicated in the problem description. There is a blank line between input blocks.
The output format consists of N output blocks. There is a blank line between output blocks.
1 9 100 200 400 300 400 300 300 400 300 400 400 500 400 500 200 350 200 200 200
1628
/* HDU 1348 凸包的周长 */ #include<iostream> #include<stdio.h> #include<math.h> #include<algorithm> using namespace std; #define N 1010 const double PI=acos(-1.0); struct point{ int x,y; }; int n,top; point p[N],s[N]; double multi(point a,point b,point c) { return (a.x-c.x)*(b.y-c.y)-(a.y-c.y)*(b.x-c.x); } double dis(point a,point b) { return sqrt(double((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y))); } int cmp(const void *a,const void *b) { double k; point c=*(point *)a; point d=*(point *)b; k=multi(p[0],c,d); if(k<0||k==0&&dis(p[0],c)>dis(p[0],d)) return 1; return -1; } void convex() { int i; point t; for(i=1;i<n;i++) { if(p[i].y<p[0].y||(p[i].y==p[0].y&&p[i].x<p[0].x)) { t=p[0]; p[0]=p[i]; p[i]=t; } } qsort(p+1,n-1,sizeof(p[0]),cmp); s[0]=p[0]; s[1]=p[1]; s[2]=p[2]; top=2; for(i=3;i<n;i++) { while(top>=2&&multi(s[top-1],s[top],p[i])<=0) top--; s[++top]=p[i]; } } int main() { int t,i,f; double ans; //freopen("test.txt","r",stdin); scanf("%d",&t); while(t--) { scanf("%d%d",&n,&f); for(i=0;i<n;i++) scanf("%d%d",&p[i].x,&p[i].y); convex(); ans=0; for(i=0;i<top;i++) ans+=dis(s[i],s[i+1]); ans+=dis(s[top],s[0]); ans+=2*PI*f; printf("%.0lf\n",ans); if(t!=0) printf("\n"); } return 0; }