HDU-OJ刷题整理（c++）Quoit Design

Posted 2021-04-03 我的头发可没乱

问题描述

Hdu oj

C++求解代码

Hdu oj

#include <cstdio>#include <algorithm>#include <cmath>using namespace std;#define N 100007
using namespace std;
struct Point{ double x,y;}pt[N];int a[N];
int n;
bool cmp(Point a, Point b){ if (a.x != b.x) return a.x < b.x; else return a.y < b.y;}bool cmp_y(int id1, int id2){ return pt[id1].y < pt[id2].y;}double getDis(const Point &a, const Point &b){ double x = a.x - b.x; double y = a.y - b.y; return sqrt(x*x + y*y);}double solve(int l, int r){ double ans = 0; if (r - l + 1 <= 3) { if (r - l + 1 == 1) return ans; ans = getDis(pt[l], pt[l + 1]); if (r - l + 1 == 2) return ans; for (int i = l; i < r; ++i) { for (int j = i + 1; j <= r; ++j) { ans = min(ans, getDis(pt[i],pt[j])); } } return ans; } int m = (l + r) >> 1; double s1 = solve(l, m); double s2 = solve(m + 1, r); ans = min(s1,s2); int k = 0; for (int i = m - 1; i >= l && pt[m].x - pt[i].x <= ans; --i) a[k++] = i; for (int i = m + 1; i <= r && pt[i].x - pt[m].x <= ans; ++i) a[k++] = i; sort(a, a + k, cmp_y); for (int i = 0; i < k; ++i) { for (int j = i + 1; j < k && j <= i + 7; ++j) { ans = min(ans, getDis(pt[a[i]], pt[a[j]])); } } return ans;}int main(){ while (~scanf("%d",&n)) { if (!n) break; for (int i = 0; i < n; ++i) scanf("%lf%lf",&pt[i].x, &pt[i].y); sort(pt, pt + n, cmp); printf("%.2lf\n",solve(0, n - 1)/2.0); } return 0;}

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