How should I practice Guaranteed Left-and-Right Sock Pair?

Start by reading the full statement, solve the visible examples, then compare the pattern against related IMC Trading phone screen problems in FastPrep.

Is Guaranteed Left-and-Right Sock Pair associated with IMC Trading?

FastPrep tags this as a IMC Trading phone screen coding practice problem when the problem catalog has that company and stage context.

Guaranteed Left-and-Right Sock Pair

IMC Trading● EasyNEW GRADPHONE SCREEN

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Problem statement

You have socks of several colors. For each color i, there are pairCounts[i] left socks and the same number of right socks.

For this exercise, assume socks are drawn one at a time without replacement in an arbitrary order. A usable pair consists of one left sock and one right sock of the same color. Two socks of the same side do not form a usable pair.

Return the minimum number of draws that guarantees at least one usable pair for every possible drawing order.

The report gives 12 red, 10 black, 8 green and 6 blue pairs. For this exercise, assume the per-color counts are an input generalizing those quantities. Complete minimumGuaranteedSockDraws(pairCounts) and return a signed 64-bit integer. The total pair count is positive.

Function

minimumGuaranteedSockDraws(pairCounts: int[]) → long

Examples

Example 1

pairCounts = [12,10,8,6]return = 37

Reported fixed case under stated assumptions. A pair-free prefix has at most 36 socks; one more guarantees a match.

Example 2

pairCounts = [1]return = 2

Authored practice example. A pair-free prefix has at most 1 socks; one more guarantees a match.

Example 3

pairCounts = [0,2,0,1]return = 4

Authored practice example. A pair-free prefix has at most 3 socks; one more guarantees a match.

Constraints

For this exercise, assume 1 <= pairCounts.length <= 10^5.
0 <= pairCounts[i] <= 10^6.
sum(pairCounts) > 0.
Each color has equally many left and right socks; drawing is without replacement.