poj3099 Go Go Gorelians 建图 DFS 回溯

#include<stdio.h>#include "math.h"int e[2001][2];//边[0],to.[1]next;int a[1001][5];//点[0],ID,[1]next;2x3y4zint c[1001];int cnum;int max;int m;bool sign[1001];int n;//点的数目int en;//边的数目void initt();void init();int DFS(int s);int eq(int x);int main(){while(1){ scanf("%d",&n); if(n==0)return 0;initt();init();int min=1000;int i;for(i=1;i<=n;i++)//n次DFS{max=0;m=0;DFS(i);if(max<min)min=max,c[1]=a[i][0],cnum=1;else if(max==min)cnum++,c[cnum]=a[i][0];else ;} if(cnum==1)printf("%d",c[1]); else { if(c[1]>c[2])printf("%d %d",c[2],c[1]); else printf("%d %d",c[1],c[2]); } printf("/n");}}int DFS(int s){if(sign[s])return 0;if((!e[a[s][1]][1])&&sign[e[a[s][1]][0]]){if(max<m){max=m; return 0;}else return 0;} m++;sign[s]=true; int next=a[s][1];while(next){DFS(e[next][0]);next=e[next][1];}m--;sign[s]=false;return 0;}void initt(){int i;cnum=0;for(i=0;i<=n;i++)a[i][1]=0;for(i=0;i<=2*n;i++) e[i][1]=0;}void init(){ int k=0;int en=0;k++;int id;int x;int y;int z;scanf("%d%d%d%d",&id,&x,&y,&z);a[k][0]=id;a[k][2]=x,a[k][3]=y,a[k][4]=z;while(k<n){k++;scanf("%d%d%d%d",&id,&x,&y,&z);a[k][0]=id;a[k][2]=x,a[k][3]=y,a[k][4]=z;int ee;ee=eq(k);en++;e[en][0]=ee;e[en][1]=a[k][1];a[k][1]=en;en++;e[en][0]=k;e[en][1]=a[ee][1];a[ee][1]=en;}}int eq(int x){int i;double min=10000;int xx;for(i=1;i<x;i++){double temp=((a[x][3]-a[i][3])*(a[x][3]-a[i][3])+(a[x][4]-a[i][4])*(a[x][4]-a[i][4])+(a[x][2]-a[i][2])*(a[x][2]-a[i][2])); double val=sqrt(temp); if(val<min)min=val,xx=i;}return xx;}