Codeforces Good Bye 2017 Div.2 908A,B

我会带着你远行 2022-05-31 10:09 187阅读 0赞

# A. New Year and Counting Cards #

## Problem Statement ##

[http://codeforces.com/contest/908/problem/A][http_codeforces.com_contest_908_problem_A]

## Analysis ##

For letter, only vowel need to know the digit in the other side.

For digit, only odd number need to know the letter in the other side.

## Code ##

#include <iostream>
    #include <string>
    using namespace std;
    
    #define MAX 50
    
    int main()
    {
        int cnt = 0;
        string s;
        cin >> s;
    
        for(int i = 0; i < s.length(); i++) 
        {
            if('a' <= s.at(i) <= 'z')
            {
                if('a' == s.at(i)|| 'e' == s.at(i) || 'i' == s.at(i) || 'o' == s.at(i) || 'u' == s.at(i))
                {
                    cnt++;
                }
            }
    
            if('0' <= s.at(i) <= '9')
            {
                if('1' == s.at(i) || '3' == s.at(i) || '5' == s.at(i) || '7' == s.at(i) || '9' == s.at(i))
                {
                    cnt++;
                }
            }
        }
    
        cout << cnt;
    }

# B. New Year and Buggy Bot #

## Problem Statement ##

[http://codeforces.com/contest/908/problem/B][http_codeforces.com_contest_908_problem_B]

## Analysis ##

(1) Bob forgot to actually assign the directions to digits, so there are 24 mapping relations between directions and digits

<table> 
 <thead> 
  <tr> 
   <th>Direction</th> 
   <th>Digit</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>0, 1, 2, 3</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>0, 1, 3, 2</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>0, 2, 1, 3</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>0, 2, 3, 1</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>0, 3, 1, 2</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>0, 3, 2, 1</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>1, 0, 2, 3</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>1, 0, 3, 2</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>1, 2, 0, 3</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>1, 2, 3, 0</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>1, 3, 0, 2</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>1, 3, 2, 0</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>2, 0, 1, 3</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>2, 0, 3, 1</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>2, 1, 0, 3</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>2, 1, 3, 0</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>2, 3, 0, 1</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>2, 3, 1, 0</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>3, 0, 1, 2</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>3, 0, 2, 1</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>3, 1, 0, 2</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>3, 1, 2, 0</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>3, 2, 0, 1</td> 
  </tr> 
  <tr> 
   <td>DOWN, UP, RIGHT, LEFT</td> 
   <td>3, 2, 1, 0</td> 
  </tr> 
 </tbody> 
</table>

(2) For C++, you can use next\_permutation() of STL to enumerate all 24 permutations.

## Code ##

#include <bits/stdc++.h>
    using namespace std;
    
    enum Dir{DOWN, UP, RIGHT, LEFT};
    const int maxn = 50;
    char grid[maxn][maxn];
    int n, m;                       // n for rows, m for columns
    int digit[4] = {
       0, 1, 2, 3};
    int startX, startY, exitX, exitY;
    string instructions;
    
    int move() 
    {
        int row = startX, col = startY;
    
        for (int i = 0; i < instructions.size(); ++i) 
        {
            int d = instructions[i] - '0';
            for (int j = 0; j < 4; ++j) 
            {
                if (d == digit[j]) 
                {
                    if (j == DOWN)
                    {
                        row++;
                    }
    
                    if (j == UP)
                    {
                        row--;
                    }
    
                    if (j == RIGHT)
                    {
                        col++;
                    }
    
                    if (j == LEFT)
                    {
                        col--;
                    }
                }
    
                if (row > n || row < 1 || col > m || col < 1)
                {
                    return 0;
                }      
                else if (grid[row][col] == 'E') 
                {
                    return 1;
                }
                else if (grid[row][col] == '#')
                {
                     return 0;
                }   
            }
        }
    
        return 0;
    }
    
    int main() 
    {
        cin >> n >> m;
        for (int i = 1; i <= n; ++i) 
        {
            for (int j = 1; j <= m; ++j) 
            {
                cin >> grid[i][j];
                if (grid[i][j] == 'S') 
                {
                    startX = i;
                    startY = j;
                }
                else if (grid[i][j] == 'E') 
                {
                    exitX = i;
                    exitY = j;
                }
            }
        }
    
        cin >> instructions;
        int res = 0;
        do 
        {
            res += move();
        } while (next_permutation(digit, digit + 4));
    
        cout << res << endl;
    
        return 0;
    }

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[http_codeforces.com_contest_908_problem_A]: http://codeforces.com/contest/908/problem/A
[http_codeforces.com_contest_908_problem_B]: http://codeforces.com/contest/908/problem/B
[wechat.jpg]: /images/20220531/da9cd57c1e44454597b9736e2a6ca06f.png