zoj 1203 Swordfish
题目链接:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=1203
解题思路:最小生成树(kruskal 算法 + 优先队列 + 并查集)
1 /************************************************************************** 2 user_id: SCNU20102200088 3 problem_id: zoj 1203 4 problem_name: Swordfish 5 **************************************************************************/ 6 7 #include <algorithm> 8 #include <iostream> 9 #include <iterator> 10 #include <iomanip> 11 #include <sstream> 12 #include <fstream> 13 #include <cstring> 14 #include <cstdlib> 15 #include <climits> 16 #include <bitset> 17 #include <string> 18 #include <vector> 19 #include <cstdio> 20 #include <cctype> 21 #include <ctime> 22 #include <cmath> 23 #include <queue> 24 #include <stack> 25 #include <list> 26 #include <set> 27 #include <map> 28 using namespace std; 29 30 //线段树 31 #define lson l,m,rt<<1 32 #define rson m+1,r,rt<<1|1 33 34 //手工扩展栈 35 #pragma comment(linker,"/STACK:102400000,102400000") 36 37 const double EPS=1e-9; 38 const double PI=acos(-1.0); 39 const double E=2.7182818284590452353602874713526; //自然对数底数 40 const double R=0.5772156649015328606065120900824; //欧拉常数:(1+1/2+...+1/n)-ln(n) 41 42 const int x4[]={-1,0,1,0}; 43 const int y4[]={0,1,0,-1}; 44 const int x8[]={-1,-1,0,1,1,1,0,-1}; 45 const int y8[]={0,1,1,1,0,-1,-1,-1}; 46 47 typedef long long LL; 48 49 typedef int T; 50 T max(T a,T b){ return a>b? a:b; } 51 T min(T a,T b){ return a<b? a:b; } 52 T gcd(T a,T b){ return b==0? a:gcd(b,a%b); } 53 T lcm(T a,T b){ return a/gcd(a,b)*b; } 54 55 /////////////////////////////////////////////////////////////////////////// 56 //Add Code: 57 int n,s[105]; 58 59 struct Node{ 60 int u,v; 61 double w; 62 bool operator <(const Node &a) const{ 63 return w>a.w; 64 } 65 }node; 66 67 priority_queue<Node> pq; 68 69 double dist(double x1,double y1,double x2,double y2){ 70 return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2)); 71 } 72 73 void Union(int x,int y){ 74 s[y]=x; 75 } 76 77 int Find(int x){ 78 if(s[x]<0) return x; 79 return s[x]=Find(s[x]); 80 } 81 82 double Kruskal(){ 83 int num=0; 84 double ret=0; 85 memset(s,-1,sizeof(s)); 86 while(!pq.empty() && num<n-1){ 87 node=pq.top(); 88 pq.pop(); 89 if(Find(node.u)!=Find(node.v)){ 90 Union(Find(node.u),Find(node.v)); 91 ret+=node.w; 92 num++; 93 } 94 } 95 while(!pq.empty()) pq.pop(); 96 return ret; 97 } 98 /////////////////////////////////////////////////////////////////////////// 99 100 int main(){ 101 std::ios::sync_with_stdio(false); 102 //freopen("in.txt","r",stdin); 103 //freopen("out.txt","w",stdout); 104 /////////////////////////////////////////////////////////////////////// 105 //Add Code: 106 int Case=1,i,j; 107 double x[105],y[105]; 108 while(scanf("%d",&n)!=EOF){ 109 if(n==0) break; 110 for(i=1;i<=n;i++) scanf("%lf%lf",&x[i],&y[i]); 111 for(i=1;i<n;i++){ 112 for(j=i+1;j<=n;j++){ 113 node.u=i; 114 node.v=j; 115 node.w=dist(x[i],y[i],x[j],y[j]); 116 pq.push(node); 117 } 118 } 119 double ans=Kruskal(); 120 if(Case>1) printf("\n"); 121 printf("Case #%d:\n",Case++); 122 printf("The minimal distance is: %.2lf\n",ans); 123 } 124 /////////////////////////////////////////////////////////////////////// 125 return 0; 126 } 127 128 /************************************************************************** 129 Testcase: 130 Input: 131 5 132 0 0 133 0 1 134 1 1 135 1 0 136 0.5 0.5 137 0 138 Output: 139 Case #1: 140 The minimal distance is: 2.83 141 **************************************************************************/
posted on 2013-10-09 09:23 SCNU20102200088 阅读(245) 评论(0) 编辑 收藏 举报