求多边形周长。角都是直角。
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1 #include <iostream> 2 #include <cstring> 3 #include <cstdio> 4 #include <cstdlib> 5 #include <algorithm> 6 7 #define N 222222 8 9 using namespace std; 10 11 struct PO 12 { 13 int x,y; 14 }p[N]; 15 16 int n; 17 18 inline bool cmpx(const PO &a,const PO &b) 19 { 20 if(a.x==b.x) return a.y<b.y; 21 return a.x<b.x; 22 } 23 24 inline bool cmpy(const PO &a,const PO &b) 25 { 26 if(a.y==b.y) return a.x<b.x; 27 return a.y<b.y; 28 } 29 30 inline void read() 31 { 32 for(int i=1;i<=n;i++) scanf("%d%d",&p[i].x,&p[i].y); 33 } 34 35 inline void go() 36 { 37 int ans=0; 38 sort(p+1,p+1+n,cmpx); 39 for(int i=1;i<=n;i+=2) ans+=p[i+1].y-p[i].y; 40 sort(p+1,p+1+n,cmpy); 41 for(int i=1;i<=n;i+=2) ans+=p[i+1].x-p[i].x; 42 printf("The length of the fence will be %d units.\n",ans); 43 } 44 45 int main() 46 { 47 while(scanf("%d",&n),n) read(),go(); 48 return 0; 49 }