stairs.go

// Tabulation
func tabulation_getminstairs(n int) int {
	table := make([]int, n+1)

	for i := 2; i <= n; i++ {
		if (i%2 == 0) && i%3 != 0 {
			table[i] = 1 + int(math.Min(float64(table[i-1]), float64(table[i/2])))
		} else if (i%3 == 0) && i%2 != 0 {

			table[i] = 1 + int(math.Min(float64(table[i-1]), float64(table[i/3])))

		} else if (i%2 == 0) && (i%3 == 0) {
			table[i] = 1 + int(math.Min(float64(table[i-1]), math.Min(float64(table[i/2]), float64(table[i/3]))))
		} else {
			table[i] = 1 + table[i-1]
		}
	}

	return table[n]
}

// Memoization
func memoization_getminstairs(n int, memo []int) int {
	if n == 1 {
		return 0
	}

	if memo[n] != 0 {
		return memo[n]
	}

	result := memoization_getminstairs(n-1, memo)

	if n%2 == 0 {
		result = int(math.Min(float64(result), float64(memoization_getminstairs(n/2, memo))))
	}

	if n%3 == 0 {
		result = int(math.Min(float64(result), float64(memoization_getminstairs(n/3, memo))))
	}

	memo[n] = 1 + result
	return memo[n]
}

// Recursion
func recursive_getminstairs(n int) int {
	if n == 1 {
		return 0
	}
	result := recursive_getminstairs(n - 1)

	if n%2 == 0 {
		result = int(math.Min(float64(result), float64(recursive_getminstairs(n/2))))
	}

	if n%3 == 0 {
		result = int(math.Min(float64(result), float64(recursive_getminstairs(n/3))))
	}

	return result + 1
}