Kth root, WA in tc 1

#1

What case am I missing, unable to find it out.

I re-wrote x^k <= n as log(x) <= (log(n)) / k and then using BS to find out x

#2

@Avi-Kasliwal-315786729062203 please share the complete code.
here base of log is e(around 2.71) so there may be many cases like x = 2, n=2, k=2 where it will return false.

#3

Link to code

#4

@Avi-Kasliwal-315786729062203
log(x) <= (log(n)) / k , it is a floating point numbers comparision (i.e. doubles and float).
Floating point operations usually involve at least tiny rounding errors which are hard to predict. Therefore two floating point operations that should mathematically give the same result (like 4.7 * (1.0 / 3.14) vs. 4.7 / 3.14) may give different results.

for their comparsion use other way around:-
bool double_equals(double a, double b, double epsilon = 0.001)
{
return abs(a - b) < epsilon;
}

Hope it helps.

1 Like
#5

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