2013
11-12

# Number-guessing Game

Larry likes playing the number-guessing game.

Two players are needed in a game. Suppose they are X and Y, and X presents a number for Y to guess. Firstly, X chooses a number with four different digits, keeping it in mind, and tells Y to start guessing. Every time Y has guessed, X should give out *A*B to show Y how close to the number his answer is. Here the symbol * stands for a number, and the number before A is the number of digits in Y's answer with both correct value and position. The number before B is the number of digits in Y's answer with correct value but incorrect position.

For example, if X chooses the number 5204, and Y guesses 4902, then X should give out 1A2B, in which 1A corresponds for digit 0 with both correct value and position and 2B corresponds for digit 2 and 4 with correct value but incorrect position. Then Y will go on guessing according to 1A2B that X presents him until he gets the totally correct number 5204 (when X shows him 4A0B).

Now you are given two numbers, and what you need to do is just testing how close they are.

The first line of the input is an integer T which indicates the number of test cases. For each test case, input two numbers. Each number contains four different digits.

For each test case, output *A*B stands for how close the two numbers are.

2
5204 4902
0123 3210


1A2B
0A4B


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import java.util.Scanner;

public class Main {
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int n = Integer.parseInt(in.nextLine());
for(int j = 0; j< n; j++)
{
String first = in.next();
String second = in.next();
int res1 = 0;
int res2 = 0;
int[] done = new int[4];
for(int i = 0; i< 4; i++)
{
if(first.charAt(i)==second.charAt(i))
{
res1++;
done[i]=1;
}
}
for(int i = 0; i< 4; i++)
{
for(int k = 0; k< 4; k++)
{
if(first.charAt(i)==second.charAt(k))
{
if(done[i]==0)
res2++;
}
}
}
System.out.println(res1+"A"+res2+"B");
}
}
}

1. Often We don’t set up on weblogs, but I would like to condition that this established up really forced me individually to do this! considerably outstanding publish

2. 老实说，这种方法就是穷举，复杂度是2^n，之所以能够AC是应为题目的测试数据有问题，要么数据量很小，要么能够得到k == t，否则即使n = 30，也要很久才能得出结果，本人亲测

3. 为什么for循环找到的i一定是素数叻，而且约数定理说的是n=p1^a1*p2^a2*p3^a3*…*pk^ak，而你每次取余都用的是原来的m，也就是n