A. Shell Game
time limit per test:0.5 seconds
memory limit per test:256 megabytes
input:standard input
output:standard output
Bomboslav likes to look out of the window in his room and watch lads outside playing famous shell game. The game is played by two persons: operator and player. Operator takes three similar opaque shells and places a ball beneath one of them. Then he shuffles the shells by swapping some pairs and the player has to guess the current position of the ball.
Bomboslav noticed that guys are not very inventive, so the operator always swaps the left shell with the middle one during odd moves (first, third, fifth, etc.) and always swaps the middle shell with the right one during even moves (second, fourth, etc.).
Let's number shells from 0 to 2 from left to right. Thus the left shell is assigned number 0, the middle shell is 1 and the right shell is 2. Bomboslav has missed the moment when the ball was placed beneath the shell, but he knows that exactly n movements were made by the operator and the ball was under shell x at the end. Now he wonders, what was the initial position of the ball?
Input
The first line of the input contains an integer n (1 ≤ n ≤ 2·109) — the number of movements made by the operator.
The second line contains a single integer x (0 ≤ x ≤ 2) — the index of the shell where the ball was found after n movements.
Output
Print one integer from 0 to 2 — the index of the shell where the ball was initially placed.
Examples
4
2 1 1
1 Note
In the first sample, the ball was initially placed beneath the middle shell and the operator completed four movements.
- During the first move operator swapped the left shell and the middle shell. The ball is now under the left shell.
- During the second move operator swapped the middle shell and the right one. The ball is still under the left shell.
- During the third move operator swapped the left shell and the middle shell again. The ball is again in the middle.
- Finally, the operators swapped the middle shell and the right shell. The ball is now beneath the right shell.
題目連結：http://codeforces.com/problemset/problem/777/A
分析：找規律，純粹找規律，你說枚舉也行！我之前搞反了，連樣例都沒過，糾結了二十分鐘才發現問題，AC了！
下面給出AC代碼：
1 #include <bits/stdc++.h>
2 using namespace std;
3 int main()
4 {
5
6 int n,m;
7 int a[3]={0,1,2};
8 while(scanf("%d",&n)!=EOF)
9 {
10 scanf("%d",&m);
11 if(n%2==0)
12 {
13 int k=n/2;
14 if(k%3==0)
15 {
16 if(m==0)
17 printf("0\n");
18 else if(m==1)
19 printf("1\n");
20 else if(m==2)
21 printf("2\n");
22 }
23 else if(k%3==1)
24 {
25 if(m==2)
26 printf("0\n");
27 else if(m==0)
28 printf("1\n");
29 else if(m==1)
30 printf("2\n");
31 }
32 else if(k%3==2)
33 {
34 if(m==1)
35 printf("0\n");
36 else if(m==2)
37 printf("1\n");
38 else if(m==0)
39 printf("2\n");
40 }
41 }
42 else
43 {
44 int t=(n+1)/2;
45 if(t%3==0)
46 {
47 if(m==0)
48 printf("0\n");
49 else if(m==2)
50 printf("1\n");
51 else if(m==1)
52 printf("2\n");
53 }
54 else if(t%3==1)
55 {
56 if(m==1)
57 printf("0\n");
58 else if(m==0)
59 printf("1\n");
60 else if(m==2)
61 printf("2\n");
62 }
63 else if(t%3==2)
64 {
65 if(m==2)
66 printf("0\n");
67 else if(m==1)
68 printf("1\n");
69 else if(m==0)
70 printf("2\n");
71 }
72 }
73 }
74 return 0;
75 } 作 者：Angel_Kitty
出 處：https://www.cnblogs.com/ECJTUACM-873284962/
關于作者：阿裡雲ACE，目前主要研究方向是Web安全漏洞以及反序列化。如有問題或建議，請多多賜教！
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