#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
时间: 2024-01-28 18:04:20 浏览: 29
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();
}
}
```