add new solutions

solutions/3/q338/solution.go

@@ -0,0 +1,11 @@
+package q338
+
+func countBits(n int) []int {
+	ret := make([]int, n+1)
+	for i := 1; i <= n; i++ {
+		ret[i] = ret[i>>1] + i%2
+	}
+	return ret
+}
+
+var _ = countBits

solutions/3/q345/solution.go

@@ -0,0 +1,31 @@
+package q345
+
+func isVowel(b byte) bool {
+	switch b {
+	case 'a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U':
+		return true
+	}
+	return false
+}
+
+func reverseVowels(s string) string {
+	edit := []byte(s)
+
+	l, r := 0, len(edit)-1
+	for l < r {
+		for l < r && !isVowel(edit[l]) {
+			l++
+		}
+		for l < r && !isVowel(edit[r]) {
+			r--
+		}
+		if l < r {
+			edit[l], edit[r] = edit[r], edit[l]
+			l++
+			r--
+		}
+	}
+	return string(edit)
+}
+
+var _ = reverseVowels

solutions/3/q374/solution.go

@@ -0,0 +1,22 @@
+package q374
+
+func guess(num int) int { panic("stub") }
+
+func guessNumber(n int) int {
+	l, r := 1, n+1
+
+	for l < r {
+		m := (l + r) / 2
+		switch guess(m) {
+		case -1: // too high
+			r = m
+		case 1: // too low
+			l = m + 1
+		case 0:
+			return m
+		}
+	}
+	return -1
+}
+
+var _ = guessNumber