write a function to calculate X^N

Question

mackerzed · Accepted Answer

int pow (int x, int n) {
    if (n == 0)
        return 1;
    if (n == 1)
        return x;
    if (n & 0x1) // n odd
        return pow(x*x, n/2) * x;
    else            // n even
        return pow(x*x, n/2);
}

Runtime: O(log n)

guest · Answer

i think you need the array way to solve it .. you all are going beyond bounds of an int

Victor · Answer

public static long pow(int x, int y)
	{
		if(y == 0 || x == 1)
			return 1;
		if(y == 1)
			return x;
		int pow = 1;
		long result = x;
		while((pow<<1) <= y)
		{
			result *= result;
			pow = pow<<1;
		}
		return result * (pow == y ? 1 : pow(x,y - pow));
	}

Almost the same solution like that from mackerzed.

Anonymous · Answer

int pow(int x, int n){
    return x*1<

Sigiloso · Answer

^^ does not work:

int pwr(int x, int n){
	int c = x;
	while(--n)
		x *= c;
	return x;
}

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