[youngDaLee] WEEK 03 Solutions

climbing-stairs/youngDaLee.go

@@ -0,0 +1,34 @@
+package youngDaLee
+
+func climbStairs(n int) int {
+	if n <= 2 {
+		return n
+	}
+
+	dp := make([]int, n+1)
+	dp[1] = 1
+	dp[2] = 2
+
+	for i := 3; i <= n; i++ {
+		dp[i] = dp[i-1] + dp[i-2]
+	}
+	return dp[n]
+}
+
+/*
+Limit Exceeded
+func climbStairs(n int) int {
+	return dfs(0, n)
+}
+
+func dfs(now, n int) int {
+	if now > n {
+		return 0
+	}
+	if now == n {
+		return 1
+	}
+
+	return dfs(now+1, n) + dfs(now+2, n)
+}
+*/

product-of-array-except-self/youngDaLee.go

@@ -0,0 +1,21 @@
+package youngDaLee
+
+func productExceptSelf(nums []int) []int {
+	n := len(nums)
+	result := make([]int, n)
+
+	// Calculate left products
+	leftProduct := 1
+	for i := 0; i < n; i++ {
+		result[i] = leftProduct
+		leftProduct *= nums[i]
+	}
+
+	// Calculate right products and combine with left products
+	rightProduct := 1
+	for i := n - 1; i >= 0; i-- {
+		result[i] *= rightProduct
+		rightProduct *= nums[i]
+	}
+	return result
+}

valid-anagram/youngDaLee.go

@@ -0,0 +1,44 @@
+package youngDaLee
+
+import "strings"
+
+func isAnagram(s string, t string) bool {
+	if len(s) != len(t) {
+		return false
+	}
+
+	if s == t {
+		return true
+	}
+
+	sDict := make(map[string]int)
+	sList := strings.Split(s, "")
+	for _, data := range sList {
+		if num, ok := sDict[data]; ok {
+			sDict[data] = num + 1
+		} else {
+			sDict[data] = 1
+		}
+	}
+
+	tList := strings.Split(t, "")
+	for _, data := range tList {
+		if num, ok := sDict[data]; ok {
+			sDict[data] = num - 1
+		} else {
+			return false
+		}
+
+		if sDict[data] < 0 {
+			return false
+		}
+	}
+
+	for _, num := range sDict {
+		if num != 0 {
+			return false
+		}
+	}
+
+	return true
+}