sgu408.java

来自「SGU题库第四版前10题的题目解答。前三题是CPP程序」· Java 代码 · 共 48 行

import java.io.*;
import java.util.*;

public class Solution implements Runnable {
	Scanner in;
	PrintWriter out;	
	int n;
	
	public void Solve() {
		n = in.nextInt();
		long ans = 0;
		if (n == 0) {
			out.println(0);
			return;
		}
		if (n == 1) {
			out.println(1);
			return;
		}
		ans = 5;
		int i, x = 2, y = 2;
		for (i = 2; i < n; i++) {
			if (x > y) y++;
			else x++;
			ans += x * y;
		}
		out.println(ans);
	}
	
	public void run() {
		try {
			in = new Scanner(new FileReader("input.txt"));
			out = new PrintWriter(System.out);
			while (in.hasNextInt())
				Solve();
			in.close();
			out.close();
		}
		catch (Exception ex) {
			ex.printStackTrace();
			System.exit(-1);
		}
	}
	
	public static void main(String args[]) {
		new Thread(new Solution()).start();
	}
}