Problema
Ver traducciónEvery person shakes hands once with every other person. A handshake between A and B is the same event as one between B and A. Nobody shakes their own hand.
Implement handshake_count(people).
Input
people: The number of people.
Output
Return the total number of distinct handshakes.
Restricciones
0 ≤ people ≤ 1,000,000,000. The answer fits a signed 64-bit integer.
Ejemplos
Ejemplo 1
Entrada:
people = 4
Salida esperada:
expected = 6Entrada:
long long people = 4;
Salida esperada:
long long expected = 6;Entrada:
long people = 4;
Salida esperada:
long expected = 6;Explicación
The pairs are AB, AC, AD, BC, BD, and CD: six handshakes.
Ejemplo 2
Entrada:
people = 1
Salida esperada:
expected = 0Entrada:
long long people = 1;
Salida esperada:
long long expected = 0;Entrada:
long people = 1;
Salida esperada:
long expected = 0;Explicación
One person has nobody else to greet.
Referencias
Este reto está adaptado para CodeUtility. Sigue el enunciado y las restricciones indicadas arriba.