C++ Algorithm and Data Structure Examples

Posted on Nov 16, 2024 in Computers

Greatest Common Divisor (GCD)

C++ Code:

#include <iostream>
using namespace std;

int gcd(int a, int b) {
    int aux;
    while (b > 0) {
        aux = b;
        b = a % b;
        a = aux;
    }
    return a;
}

Base Conversion

C++ Code:

#include <iostream>
using namespace std;

void base2(int n) {
    if (n <= 1) cout << n;
    else {
        base2(n / 2);
        cout << n % 2;
    }
}

void base8(int n) {
    if (n / 8 == 0) cout << n;
    else {
        base8(n / 8);
        cout << n % 8;
    }
}

void base16(int n) {
    if (n / 16 == 0) {
        if (n == 10) {
            cout << 'A';
        } else if (n == 11) {
            cout << 'B';
        } else if (n == 12) {
            cout << 'C';
        } else if (n == 13) {
            cout << 'D';
        } else if (n == 14) {
            cout << 'E';
        } else if (n == 15) {
            cout << 'F';
        } else {
            cout << n;
        }
    } else {
        base16(n / 16);
        int mod;
        mod = n % 16;
        if (mod == 10) {
            cout << 'A';
        } else if (mod == 11) {
            cout << 'B';
        } else if (mod == 12) {
            cout << 'C';
        } else if (mod == 13) {
            cout << 'D';
        } else if (mod == 14) {
            cout << 'E';
        } else if (mod == 15) {
            cout << 'F';
        } else {
            cout << mod;
        }
    }
}

int main() {
    int n;
    while (cin >> n) {
        cout << n << " = ";
        base2(n);
        cout << ", ";
        base8(n);
        cout << ", ";
        base16(n);
        cout << endl;
    }
}

Consecutive Repeated Words

C++ Code:

#include <iostream>
#include <string>
using namespace std;

int main() {
    int max = 1, act = 1;
    string pact, sbusc;

    cin >> sbusc;

    while (cin >> pact) {
        if (sbusc == pact) {
            act++;
            if (act > max) {
                max = act;
            }
        } else {
            act = 0; // Reset count if words are different
        }
    }
    cout << max << endl;
}

Primality Test

C++ Code:

#include <iostream>
#include <cmath>

using namespace std;

bool esprimer(int n) {
    int i = 3;
    bool p = true;
    int max;
    max = sqrt(n);

    if (n == 2) p = true;
    else if (n == 1) p = false;
    else if (n % 2 == 0) p = false;
    else {
        while (i <= max and p) {
            if (n % i == 0) p = false;
            i = i + 2;
        }
    }
    return p;
}

int main() {
    int n, p;

    cin >> n;

    while (n > 0) {
        cin >> p;
        cout << p;
        if (not esprimer(p)) cout << " no";
        cout << " es primer" << endl;
        n--;
    }
}

Balanced Numbers

C++ Code:

#include <iostream>
using namespace std;

bool es_equilibrat(int n) {
    int numimp = 0, numpar = 0;
    while (n > 0) {
        numimp += n % 10;
        n /= 10;
        numpar += n % 10;
        n /= 10;
    }
    if (numimp == numpar) return true;
    return false;
}

int main() {
    int n;
    cin >> n;
    if (es_equilibrat(n)) cout << "si" << endl;
    else cout << "no" << endl;
}

Valid Dates

C++ Code:

#include <iostream>
using namespace std;

bool es_any_de_traspas(int any) {
    if ((any % 4 == 0 && any % 100 != 0) || any % 400 == 0) {
        return true;
    } else {
        return false;
    }
}

bool es_data_valida(int d, int m, int a) {
    if (d > 0 && d < 32 && m > 0 && m < 13) {
        if (m == 1 || m == 3 || m == 5 || m == 7 || m == 8 || m == 10 || m == 12) { // 31 days
            if (d < 32) {
                return true;
            } else {
                return false;
            }
        } else if (m == 2) { // February
            if (es_any_de_traspas(a)) {
                if (d < 30) {
                    return true;
                } else {
                    return false;
                }
            } else {
                if (d < 29) {
                    return true;
                } else {
                    return false;
                }
            }
        } else { // 30 days
            if (d < 31) {
                return true;
            } else {
                return false;
            }
        }
    } else {
        return false;
    }
}

int main() {
    int d, m, a;

    cin >> d >> m >> a;

    cout << es_data_valida(d, m, a) << endl;
}

Least Common Multiple (LCM)

C++ Code:

#include <iostream>
using namespace std;

int gcd(int a, int b) {
    int aux;
    while (b > 0) {
        aux = b;
        b = a % b;
        a = aux;
    }
    return a;
}

int lcm(int a, int b) {
    return ((a) / gcd(a, b)) * b;
}

int main() {
    int n;
    int a, b;
    int mincum;
    while (cin >> n and n != 0) {
        if (n == 1) {
            cin >> a;
            cout << a << endl;
        } else {
            cin >> a;
            for (int i = 0; i < n - 1; ++i) {
                cin >> b;
                mincum = lcm(a, b);
                a = mincum;
            }
            cout << mincum << endl;
        }
    }
}

Digit Reduction

C++ Code:

#include <iostream>
using namespace std;

int suma_digits(int x) {
    if (x / 10 == 0) {
        return x;
    } else {
        return x % 10 + suma_digits(x / 10);
    }
}

int reduccio_digits(int x) {
    if (x < 10) {
        return x;
    }
    return reduccio_digits(suma_digits(x));
}

int main() {
    int n;
    cin >> n;
    cout << reduccio_digits(n) << endl;
}

Reversing a List of Words

C++ Code:

#include <iostream>
#include <string>
using namespace std;

int gira_paraules(int n) {
    string mot;

    if (not(cin >> mot)) {
        return 0;
    }
    int d = gira_paraules(n);
    if (d < n) {
        cout << mot << endl;
    }
    return d + 1;
}

int main() {
    int n;
    cin >> n;
    gira_paraules(n);
}

Maximum of Each Sequence

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int n, act, max, i = 0;
    while (cin >> n) {
        cin >> max;
        while (i < n - 1) {
            cin >> act;
            if (act >= max) {
                max = act;
            }
            i++;
        }
        cout << max << endl;
        i = 0; // Reset i for the next sequence
    }
}

Caesar Cipher

C++ Code:

#include <iostream>
using namespace std;

int main() {
    int n, ic;
    char c;

    while (cin >> n) {
        while (cin >> c && c != '.') {
            if ((int)c >= 97 && (int)c <= 122) {
                ic = (int)c;
                ic += n;
                while (ic > 122) {
                    ic = ic - 26;
                }
                ic = ic - 32; // Convert to uppercase
                cout << (char)ic;
            } else if (c == '_') {
                cout << ' ';
            } else {
                cout << c;
            }
        }
        cout << endl;
    }
}