ianadiwibowo/central-park

package main

func MaxCircle(queries [][]int32) (largestSizes []int32) {
    friendships := [][]int32{}
    friendshipLocator := make(map[int32]int)

    // Checking each person existing friendship
    for _, query := range queries {
        var sets [2][]int32
        for i, person := range query {
            index := friendshipLocator[person]
            if index != 0 {
                sets[i] = friendships[index-1]
            } else {
                sets[i] = []int32{person}
            }
        }

        // Make them friends
        newFriendship := append(sets[0], sets[1]...)
        friendships = append(friendships, newFriendship)

        friendshipLocator = update(friendshipLocator, friendships, newFriendship)
        largestSizes = findLargestSize(largestSizes, newFriendship)
    }

    return largestSizes
}

func update(
    friendshipLocator map[int32]int,
    friendships [][]int32,
    newFriendship []int32,
) map[int32]int {
    lastFriendGroupIndex := len(friendships)
    for _, person := range newFriendship {
        friendshipLocator[person] = lastFriendGroupIndex
    }
    return friendshipLocator
}

func findLargestSize(largestSizes []int32, newFriendship []int32) []int32 {
    prevLargestSize := getPrevLargestSize(largestSizes)

    newSize := int32(len(newFriendship))
    if newSize > prevLargestSize {
        largestSizes = append(largestSizes, newSize)
    } else {
        largestSizes = append(largestSizes, prevLargestSize)
    }

    return largestSizes
}

func getPrevLargestSize(largestSizes []int32) (prevLargestSize int32) {
    l := len(largestSizes)
    if l > 0 {
        prevLargestSize = largestSizes[l-1]
    }
    return prevLargestSize
}