HDU ACM OJ 1000 1001 1002答案(JAVA)

HDU OJ比较简单的三道题。主要是熟悉一下格式和写法。

1000：

import java.util.Scanner;

/**
 * Calculate A + B.
 * @author Jamin
 *
 */
public class Main {

	public static void main(String arg[]) {
		Scanner scin = new Scanner(System.in);
		while (scin.hasNextInt()) {
			int a = scin.nextInt();
			int b = scin.nextInt();
			System.out.println(a + b);
		}
	}
}

1001：

import java.util.Scanner;


/**
 * In this problem,your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.
 * @author Jamin
 *
 */
public class Main {

	
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		while(scanner.hasNext()){
			int n = scanner.nextInt();
			if(n % 2 == 0){
				int sum = n/2 * (n + 1);
				System.out.println(sum);
				System.out.println();
			}else{
				int sum = (n + 1) /2 *n;
				System.out.println(sum);
				System.out.println();
			}
		}
	}
}

1002：

import java.math.BigInteger;
import java.util.Scanner;

/**
 * I have a very simple problem for you. 
 * Given two integers A and B, 
 * your job is to calculate the Sum of A + B.
 * @author Jamin
 *
 */
public class Main {
	

	//374MS	11520K	1062B
	//312MS	11452K	1083B
	public static void main(String[] args) {
		
		Scanner scanner = new Scanner(System.in);
		int num = scanner.nextInt();
		BigInteger a , b;
		StringBuilder stringBuilder = new StringBuilder();
		for(int i = 1 ; i<= num; i++){
			stringBuilder.setLength(0);
			a = scanner.nextBigInteger();
			b = scanner.nextBigInteger();
			//case 1:
			stringBuilder.append("Case ");
			stringBuilder.append(i);
			stringBuilder.append(":");
			System.out.println(stringBuilder);
			//a + b = sum
			stringBuilder.setLength(0);
			stringBuilder.append(a);
			stringBuilder.append(" + ");
			stringBuilder.append(b);
			stringBuilder.append(" = ");
			stringBuilder.append(a.add(b));
			System.out.println(stringBuilder);
			//if not last line add block line after result
			if(i < num){
				System.out.println();
			}
		}
	}
	
	
//	//327MS	11660K
//	//358MS	11664K	564B
//	public static void main(String[] args) {
//		
//		Scanner scanner = new Scanner(System.in);
//		int num = scanner.nextInt();
//		BigInteger a , b;
//		for(int i = 1 ; i<= num; i++){
//			a = scanner.nextBigInteger();
//			b = scanner.nextBigInteger();
//			System.out.println("Case " + i +":");
//			System.out.println(a + " + " + b + " = " + a.add(b));
//			if(i < num){
//				System.out.println();
//			}
//		}
//	}
	
	
}