Java面向对象4（P~U）

P    3-1 Point类的构造函数 （SDUT 2670）

import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x,y;
		x = sc.nextInt();
		y = sc.nextInt();
		System.out.println("(0,0)");
		System.out.println("(" + x + "," + y + ")");
	}
}

最佳拟合直线(SDUT 2728)

import java.util.Scanner;
 
public class Main {
	static int n;
	static double sum(double x[])  
	{  
	    double s=0;  
	    for(int i=0;i<n;i++)  
	    s+=x[i];  
	    return s;   
	}
	public static void main(String[] args) {
		Scanner  in = new Scanner(System.in);
		double x[] = new double [20];
		double y[] = new double [20];
		double c[] = new double [20];
		double d[] = new double [20];
		double a1,b1,o;
		n = in.nextInt();
		for(int i = 0; i < n; i++){
			x[i] = in.nextDouble();
			y[i] = in.nextDouble();
			c[i] = x[i] * y[i];
			d[i] = x[i] * x[i];
		}
		a1 = n * sum(c) - sum(x) * sum(y);
		b1 = sum(y) * sum(d) -sum(x) * sum(c);
		o = n * sum(d) - Math.pow(sum(x), 2);
		System.out.printf("%.3f\n",a1/o);
		System.out.printf("%.3f\n",b1/o);
	}
}
	 

区域内点的个数(SDUT 2749)

//转载
import java.util.Scanner;
 
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while (sc.hasNext()) {
			int count = sc.nextInt();
			Point[] points = new Point[count];
			int px1 = sc.nextInt();
			int py1 = sc.nextInt();
			int px2 = sc.nextInt();
			int py2 = sc.nextInt();
			Point p1 = new Point(px1, py1);
			Point p2 = new Point(px2, py2);
			int resultCount = 0;
			for (int i = 0; i < count; i++) {
				points[i] = new Point(sc.nextInt(), sc.nextInt());
				if (points[i].inRect(p1, p2)) {
					resultCount++;
				}
			}
			System.out.println(resultCount);
		}
 
		sc.close();
	}
}
 
class Point {
	int x;
	int y;
 
	public Point(int x, int y) {
		this.x = x;
		this.y = y;
	}
 
	public boolean inRect(Point p1, Point p2) {
		boolean flag = false;
		if (x > p1.x && x < p2.x && y > p1.y && y < p2.y) {
			flag = true;
		}
		return flag;
	}
}

谁是最强的女汉子（SDUT 3081）

import java.text.DecimalFormat;
import java.util.Scanner;
 
public class Main {
 
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		long []a = new long [11000]; 
		long []b = new long [11000];
		int n = sc.nextInt();
	    a[0] = sc.nextLong();
	    b[0] = sc.nextLong();
	    long min = a[0];
	    int c = 0;
	    long sum = 0;
		for(int i = 1 ;i < n; i++) {
			a[i] = sc.nextLong();
			b[i] = sc.nextLong();
			if(min > a[i]) {
				min = a[i];
			}
		}
		for(int i = 0 ;i < n ; i ++) {
			if(min == a[i]) {
				c++;
				sum += b[i];
			}
		}
		System.out.println(c+" "+sum);
}
}

飞花的糖果（SDUT 3268）

import java.util.Scanner;  
class Candy{
	int m, n;
	public Candy(int n, int m) {
		super();
		this.m = m;
		this.n = n;
	}
	
	public int count() {
		int s1 =1;
		int s2 =1;
		for(int i=n; i>n-m; i--) {
			s1 *= i;
		}
		for(int i=2; i<=m; i++) {
			s2 *= i;
		}
		return s1/s2;
	}
	
}
public class Main  {  
   public static void main(String[] args) {  
      Scanner reader = new Scanner(System.in);  
      while(reader.hasNext()) {
    	  int n = reader.nextInt();
    	  int m = reader.nextInt();
    	  Candy candy = new Candy(n, m);
    	  System.out.println(candy.count());
      }
   }  
}   

 计算长方体、四棱锥的表面积和体积（SDUT 3337）

 

import java.text.DecimalFormat;
import java.util.Scanner;

public class Main {
	
	public static void main(String[] args) {
		Scanner in = new Scanner (System.in);
		while( in.hasNext() ){
			double l = in.nextInt();
			double h = in.nextInt();
			double z = in.nextInt();
			Cubic cub = new Cubic(l, h, z);
			Pyramid py = new Pyramid(l, h, z);
			DecimalFormat m = new DecimalFormat("0.00");
			System.out.println(m.format(cub.area()) + " " + m.format(cub.volumn()) +" "
					+ m.format(py.area()) + " " + m.format(py.volumn()) );
		}
		in.close();
	}
}
 
class Rect {
	double leng, high, zi;
	
	public Rect(double l, double h, double z ){
		if( l>0 && h>0 && z>0 ){
			this.leng = l;
			this.high = h;
			this.zi = z;
		}
	}
	
	public double length(){
		return 2*(leng+high);
	}
	
	public double area(){
		return leng*high;
	}
}
 
class Cubic extends Rect{
	
	public Cubic (double l, double h, double z ){
		super(l, h, z);	
	}
	
	public double area(){
		return 2*super.area()+length()*zi;
	}
	
	public double volumn(){
		return super.area()*zi;
	}
}
 
class Pyramid extends Rect{
	public Pyramid( double l, double h, double z ){
		super(l, h, z);
	}
	
	public double area(){
		return super.area() + leng*Math.sqrt(zi*zi+high*high/4) + high*Math.sqrt(zi*zi+leng*leng/4);
	}
	
	public double volumn(){
		return super.area()*zi/3;
	}
}