#define?_CRT_SECURE_NO_WARNINGS #include?<iostream>?? #include?<cmath>?? #include?<algorithm>?? #define?MAXN?100005?? using?namespace?std; struct?Point { double?x,?y; }; struct?Point?point[MAXN],?*px[MAXN],?*py[MAXN]; double?get_dis(Point?*p1,?Point?*p2) { return?sqrt((p1->x?-?p2->x)*(p1->x?-?p2->x)?+?(p1->y?-?p2->y)*(p1->y?-?p2->y)); } bool?cmpx(Point?*p1,?Point?*p2)?{?return?p1->x<p2->x;?} bool?cmpy(Point?*p1,?Point?*p2)?{?return?p1->y<p2->y;?} double?min(double?a,?double?b)?{?return?a<b???a?:?b;?} //-------核心代碼------------//?? double?closest(int?s,?int?e) { if?(s?+?1?==?e) return?get_dis(px[s],?px[e]); if?(s?+?2?==?e) return?min(get_dis(px[s],?px[s?+?1]),?min(get_dis(px[s?+?1],?px[e]),?get_dis(px[s],?px[e]))); int?mid?=?(s?+?e)?>>?1; double?ans?=?min(closest(s,?mid),?closest(mid?+?1,?e));//遞歸求解?? int?i,?j,?cnt?=?0; for?(i?=?s;i?<=?e;i++)//把x坐標(biāo)在px[mid].x-ans~px[mid].x+ans范圍內(nèi)的點(diǎn)取出來(lái)?? { if?(px[i]->x?>=?px[mid]->x?-?ans&&px[i]->x?<=?px[mid]->x?+?ans) py[cnt++]?=?px[i]; } sort(py,?py?+?cnt,?cmpy);//按y坐標(biāo)排序?? for?(i?=?0;i<cnt;i++) { for?(j?=?i?+?1;j<cnt;j++)//py數(shù)組中的點(diǎn)是按照y坐標(biāo)升序的?? { if?(py[j]->y?-?py[i]->y?>=?ans) break; ans?=?min(ans,?get_dis(py[i],?py[j])); } } return?ans; } int?main() { int?i,?n; while?(scanf("%d",?&n)?!=?EOF) { if?(n?==?0) break; for?(i?=?0;i<n;i++) { scanf("%lf%lf",?&point[i].x,?&point[i].y); px[i]?=?&point[i]; } sort(px,?px?+?n,?cmpx); //for(i=0;i<n;i++)?? //?printf("(%.2lf,%.2lf)--",px[i].x,px[i].y);?? double?distance?=?closest(0,?n?-?1); printf("%.2lf\n",?distance?/?2); } return?0; }