HackerRank Fundamentals – Army Game

Challenge: Army Game

Subdomeniu: Fundamentals (fundamentals)

Scor cont: 10.0 / 10

Submission status: Accepted

Submission score: 1.0

Submission ID: 464719171

Limbaj: cpp14

Link challenge: https://www.hackerrank.com/challenges/game-with-cells/problem

Cerinta

Luke is daydreaming in Math class. He has a sheet of graph paper with $n$ rows and $m$ columns, and he imagines that there is an army base in each cell for a total of $n \cdot m$ bases. He wants to drop supplies at strategic points on the sheet, marking each drop point with a red dot. If a base contains at least one package inside or on top of its border fence, then it's considered to be supplied. For example:

![image](https://s3.amazonaws.com/hr-challenge-images/0/1479944215-79f12638a7-example-army-game.png)

Given $n$ and $m$, what's the minimum number of packages that Luke must drop to supply all of his bases?  

**Example**  
$n = 2$  
$m = 3$  

Packages can be dropped at the corner between cells (0, 0), (0, 1), (1, 0) and (1, 1) to supply $4$ bases.  Another package can be dropped at a border between (0, 2) and (1, 2).  This supplies all bases using $2$ packages.  

**Function Description**  

Complete the *gameWithCells* function in the editor below.  

*gameWithCells* has the following parameters:  

- *int n:* the number of rows in the game  
- *int m:* the number of columns in the game  

**Returns**  

- *int:* the minimum number of packages required

Input Format

Two space-separated integers describing the respective values of $n$ and $m$.

Constraints

$0 \lt n, m \le 1000$

Cod sursa

#include <bits/stdc++.h>

using namespace std;

string ltrim(const string &);
string rtrim(const string &);
vector<string> split(const string &);

int gameWithCells(int n, int m) {
return ceil(n/2.0)*ceil(m/2.0);
}
int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    string first_multiple_input_temp;
    getline(cin, first_multiple_input_temp);

    vector<string> first_multiple_input = split(rtrim(first_multiple_input_temp));

    int n = stoi(first_multiple_input[0]);

    int m = stoi(first_multiple_input[1]);

    int result = gameWithCells(n, m);

    fout << result << "\n";

    fout.close();

    return 0;
}

string ltrim(const string &str) {
    string s(str);

    s.erase(
        s.begin(),
        find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace)))
    );

    return s;
}

string rtrim(const string &str) {
    string s(str);

    s.erase(
        find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
        s.end()
    );

    return s;
}

vector<string> split(const string &str) {
    vector<string> tokens;

    string::size_type start = 0;
    string::size_type end = 0;

    while ((end = str.find(" ", start)) != string::npos) {
        tokens.push_back(str.substr(start, end - start));

        start = end + 1;
    }

    tokens.push_back(str.substr(start));

    return tokens;
}