计蒜客竞赛基础，最近点对问题

#include <iostream>#include <algorithm>#include <cstring>#include <cmath>#define INF 100002using namespace std;struct point {double x;double y;};point p[100002];point p1[100002];point p2[100002];//point flagp[6];bool cmpx(point a, point b) {if (a.x != b.x) {return a.x < b.x;}else {return a.y < b.y;}}bool cmpy(point a, point b) {if (a.y != b.y) {return a.y < b.y;}else {return a.x > b.x;}}double func(int number, int left, int right) {double len1, len2, minlen, l;int num1, num2, k = 0;if (number == 2) {return sqrt((p[left].x - p[right].x) * (p[left].x - p[right].x) +(p[left].y - p[right].y) * (p[left].y - p[right].y));}else if (number < 2) {return INF;}else {num1 = number / 2;num2 = number - num1;len1 = func(num1, left, left + num1 - 1);len2 = func(num2, left + num1, right);minlen = len1 < len2 ? len1 : len2;l = (p[(left + right - 1) / 2].x + p[(left + right - 1) / 2 + 1].x) / 2;for (int i = left; i <= (left + right - 1) / 2; i++) {if (fabs(p[i].x - l) < minlen) {p1[k].x = p[i].x;p1[k].y = p[i].y;k++;}}sort(p1, p1 + k, cmpy);int k2 = 0;for (int i = (left + right - 1) / 2 + 1; i <= right; i++) {if (fabs(l - p[i].x) < minlen) {p2[k2].x = p[i].x;p2[k2].y = p[i].y;k2++;}}sort(p2, p2 + k2, cmpy);double flaglen = INF;for (int i = 0; i < k; i++) {for (int j = 0; j < k2; j++) {if (p2[j].y - p1[i].y < minlen) {flaglen = sqrt((p2[j].x - p1[i].x) * (p2[j].x - p1[i].x) + (p2[j].y - p1[i].y) * (p2[j].y - p1[i].y));if (flaglen < minlen) {minlen = flaglen;}}}}return minlen;}}int main() {int num;cin >> num;for (int i = 0; i < num; i++) {cin >> p[i].x >> p[i].y;}sort(p, p + num, cmpx);cout << func(num, 0, num - 1) << endl;return 0;}