#include<iostream> #include<cmath> #include<algorithm> using namespace std; struct point { int x, y, index; double theta; } p[30000], temp; int f(point& a, point& b) { if (a.theta == b.theta) { if (a.x == b.x && a.y > 0) return a.y * a.y > b.y * b.y; else return a.x * a.x + a.y * a.y < b.x* b.x + b.y * b.y; }return a.theta < b.theta; }int main() { int n; cin >> n; //input for (int i = 0; i < n; i++) { int x, y; cin >> p[i].x >> p[i].y; p[i].index = i + 1; }//exchange min_x to first position int min = p[0].x, minPosition = 0; for (int i = 1; i < n; i++) { minPosition = min <= p[i].x ? minPosition : i; min = min <= p[i].x ? min : p[i].x; }temp = p[0]; p[0] = p[minPosition]; p[minPosition] = temp; //cal atan2 for (int i = 1; i < n; i++) { p[i].x -= p[0].x; p[i].y -= p[0].y; p[i].theta = atan2(p[i].y, p[i].x); }//sort exclude min_x sort(p + 1, p + n, f); //output cout << n << endl; for (int i = 0; i < n; i++) { if (p[i].index == 1) { for (int j = i; j < n; j++) cout << p[j].index << endl; for (int j = 0; j < i; j++) cout << p[j].index << endl; break; } } }转为Java

以下是将给定的 C++ 代码转换为 Java 代码的结果： ```java import java.util.Arrays; import java.util.Comparator; import java.util.Scanner; public class Main { static class Point { int x, y, index; double theta; public Point(int x, int y, int index, double theta) { this.x = x; this.y = y; this.index = index; this.theta = theta; } } static Point[] p = new Point[30000]; static int f(Point a, Point b) { if (a.theta == b.theta) { if (a.x == b.x && a.y > 0) return a.y * a.y > b.y * b.y ? 1 : -1; else return a.x * a.x + a.y * a.y < b.x * b.x + b.y * b.y ? 1 : -1; } return a.theta < b.theta ? 1 : -1; } public static void main(String[] args) { Scanner scan = new Scanner(System.in); int n = scan.nextInt(); // input for (int i = 0; i < n; i++) { int x = scan.nextInt(); int y = scan.nextInt(); p[i] = new Point(x, y, i + 1, 0); } // exchange min_x to first position int min = p[0].x, minPosition = 0; for (int i = 1; i < n; i++) { minPosition = min <= p[i].x ? minPosition : i; min = min <= p[i].x ? min : p[i].x; } Point temp = p[0]; p[0] = p[minPosition]; p[minPosition] = temp; // cal atan2 for (int i = 1; i < n; i++) { p[i].x -= p[0].x; p[i].y -= p[0].y; p[i].theta = Math.atan2(p[i].y, p[i].x); } // sort exclude min_x Arrays.sort(p, 1, n, new Comparator<Point>() { @Override public int compare(Point a, Point b) { return f(a, b); } }); // output System.out.println(n); for (int i = 0; i < n; i++) { if (p[i].index == 1) { for (int j = i; j < n; j++) System.out.println(p[j].index); for (int j = 0; j < i; j++) System.out.println(p[j].index); break; } } scan.close(); } } ```