For a given n and m, compute the sum sigma = 1^n + 2^n + 3^n + ... + m^n and print it.
Example
Input:
let n = 2
let m = 5Expected value/output:
55
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Hint
Change the function for computing powers of 2, to compute powers of ainstead and add them up to m.
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Solution
let n = 2
let m = 5
func powaN(N:Int, a:Int) -> Int {
if N == 0 {
return 1
}
else {
var halfN = N/2
var halfpowaN = powaN(N: halfN, a: a)
var res = halfpowaN * halfpowaN
if N - halfN > halfN {
res *= a
}
return res
}
}
func sumOfPowers(N:Int, M:Int) -> Int {
var sum = 0
for i in 1...M {
sum += powaN(N:N, a:i)
}
return sum
}
print(sumOfPowers(N:n, M:m))[collapse]
