Kraft Check

Given a list of codeword lengths, determine whether a prefix-free code can exist.

Function

func KraftSatisfied(lengths []int) bool

Behavior

• lengths[i] == 0 means the symbol is unused and should be ignored.
• Return true iff sum 2^{-lengths[i]} <= 1.
• If lengths is empty, return true.

Constraints

• Each length is 0 <= l <= 30 (fits in 64-bit integer arithmetic).

Notes

• Avoid floating-point error by using integer arithmetic.