Algorithm, Data structure/Solved Algorithmic Problem

USACO 1.3 - Combination Lock

JaykayChoi 2016. 6. 17. 00:00

Farmer John's cows keep escaping from his farm and causing mischief. To try and prevent them from leaving, he purchases a fancy combination lock to keep his cows from opening the pasture gate.

Knowing that his cows are quite clever, Farmer John wants to make sure they cannot easily open the lock by simply trying many different combinations. The lock has three dials, each numbered 1..N (1 <= N <= 100), where 1 and N are adjacent since the dials are circular. There are two combinations that open the lock, one set by Farmer John, and also a "master" combination set by the lock maker.

The lock has a small tolerance for error, however, so it will open even if the numbers on the dials are each within at most 2 positions of a valid combination.

For example, if Farmer John's combination is (1,2,3) and the master combination is (4,5,6), the lock will open if its dials are set to (1,3,5) (since this is close enough to Farmer John's combination) or to (2,4,8) (since this is close enough to the master combination). Note that (1,5,6) would not open the lock, since it is not close enough to any one single combination.

Given Farmer John's combination and the master combination, please determine the number of distinct settings for the dials that will open the lock. Order matters, so the setting (1,2,3) is distinct from (3,2,1).

PROGRAM NAME: combo

INPUT FORMAT:

Line 1:The integer N.
Line 2:Three space-separated integers, specifying Farmer John's combination.
Line 3:Three space-separated integers, specifying the master combination (possibly the same as Farmer John's combination).

SAMPLE INPUT (file combo.in):

50
1 2 3
5 6 7

INPUT DETAILS:

Each dial is numbered 1..50. Farmer John's combination is (1,2,3), and the master combination is (5,6,7).

OUTPUT FORMAT:

Line 1:The number of distinct dial settings that will open the lock.

SAMPLE OUTPUT (file combo.out):

249

SAMPLE OUTPUT EXPLANATION

Here's a list:

1,1,1  2,2,4  3,4,2  4,4,5  5,4,8  6,5,6  7,5,9  3,50,2  50,1,4 
1,1,2  2,2,5  3,4,3  4,4,6  5,4,9  6,5,7  7,6,5  3,50,3  50,1,5 
1,1,3  2,3,1  3,4,4  4,4,7  5,5,5  6,5,8  7,6,6  3,50,4  50,2,1 
1,1,4  2,3,2  3,4,5  4,4,8  5,5,6  6,5,9  7,6,7  3,50,5  50,2,2 
1,1,5  2,3,3  3,4,6  4,4,9  5,5,7  6,6,5  7,6,8  49,1,1  50,2,3 
1,2,1  2,3,4  3,4,7  4,5,5  5,5,8  6,6,6  7,6,9  49,1,2  50,2,4 
1,2,2  2,3,5  3,4,8  4,5,6  5,5,9  6,6,7  7,7,5  49,1,3  50,2,5 
1,2,3  2,4,1  3,4,9  4,5,7  5,6,5  6,6,8  7,7,6  49,1,4  50,3,1 
1,2,4  2,4,2  3,5,5  4,5,8  5,6,6  6,6,9  7,7,7  49,1,5  50,3,2 
1,2,5  2,4,3  3,5,6  4,5,9  5,6,7  6,7,5  7,7,8  49,2,1  50,3,3 
1,3,1  2,4,4  3,5,7  4,6,5  5,6,8  6,7,6  7,7,9  49,2,2  50,3,4 
1,3,2  2,4,5  3,5,8  4,6,6  5,6,9  6,7,7  7,8,5  49,2,3  50,3,5 
1,3,3  3,1,1  3,5,9  4,6,7  5,7,5  6,7,8  7,8,6  49,2,4  50,4,1 
1,3,4  3,1,2  3,6,5  4,6,8  5,7,6  6,7,9  7,8,7  49,2,5  50,4,2 
1,3,5  3,1,3  3,6,6  4,6,9  5,7,7  6,8,5  7,8,8  49,3,1  50,4,3 
1,4,1  3,1,4  3,6,7  4,7,5  5,7,8  6,8,6  7,8,9  49,3,2  50,4,4 
1,4,2  3,1,5  3,6,8  4,7,6  5,7,9  6,8,7  1,50,1 49,3,3  50,4,5 
1,4,3  3,2,1  3,6,9  4,7,7  5,8,5  6,8,8  1,50,2 49,3,4  49,50,1
1,4,4  3,2,2  3,7,5  4,7,8  5,8,6  6,8,9  1,50,3 49,3,5  49,50,2
1,4,5  3,2,3  3,7,6  4,7,9  5,8,7  7,4,5  1,50,4 49,4,1  49,50,3
2,1,1  3,2,4  3,7,7  4,8,5  5,8,8  7,4,6  1,50,5 49,4,2  49,50,4
2,1,2  3,2,5  3,7,8  4,8,6  5,8,9  7,4,7  2,50,1 49,4,3  49,50,5
2,1,3  3,3,1  3,7,9  4,8,7  6,4,5  7,4,8  2,50,2 49,4,4  50,50,1
2,1,4  3,3,2  3,8,5  4,8,8  6,4,6  7,4,9  2,50,3 49,4,5  50,50,2
2,1,5  3,3,3  3,8,6  4,8,9  6,4,7  7,5,5  2,50,4 50,1,1  50,50,3
2,2,1  3,3,4  3,8,7  5,4,5  6,4,8  7,5,6  2,50,5 50,1,2  50,50,4
2,2,2  3,3,5  3,8,8  5,4,6  6,4,9  7,5,7  3,50,1 50,1,3  50,50,5
2,2,3  3,4,1  3,8,9  5,4,7  6,5,5  7,5,8


출처: http://train.usaco.org/



N개의 숫자로 이루어진 자물쇠가 존재한다고 할 때 자물쇠에는 일반 키 조합과 마스터 키 조합이 있습니다. 자물쇠의 문제 때문에 인접한 +- 2 의 숫자까지도 제대로된 값으로 인식한다고 할 때 열 수 있는 숫자의 조합의 개수를 출력하는 문제입니다. 숫자는 원형으로 되어 있기 때문에 50 다음의 숫자는 1입니다.

중복된 답을 피하기위해 set container 을 사용해 풀었습니다.



my solving

c++

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#include <fstream>
#include <iostream>
#include <string>
#include <set>
#include <algorithm>
using namespace std;
 
int n;
set<string> dialSettings;
 
int getPosition(int pos)
{
    while (pos < 0)
        pos += n;
 
    if (pos > n)
        pos %= n;
    
    if (pos == 0)
        pos = n;
 
    return pos;
}
 
void setDial(int *combination)
{
    for (int i = -2; i < 3; i++)
    {
        for (int j = -2; j < 3; j++)
        {
            for (int k = -2; k < 3; k++)
            {
                string str = to_string(getPosition(combination[0+ i)) + to_string(getPosition(combination[1+ j)) + to_string(getPosition(combination[2+ k));
                dialSettings.insert(str);
            }
        }
    }
}
int main()
{
    ofstream fout("combo.out");
    ifstream fin("combo.in");
 
    fin >> n;
 
    int farmarCombination[3];
    int masterCombination[3];
    
    for (int i = 0; i < 3; i++)
    {
        int num;
        fin >> num;
        farmarCombination[i] = num;
    }
    for (int i = 0; i < 3; i++)
    {
        int num;
        fin >> num;
        masterCombination[i] = num;
    }
 
    setDial(farmarCombination);
    setDial(masterCombination);
 
    fout << dialSettings.size() << endl;
 
fin.close();
fout.close();
    return 0;
}
cs