Add: Ugly Number II

internal/leetcode/problems_status.go

@@ -89,6 +89,8 @@ var problemStatus = map[int]bool{
 	237:  true,
 	242:  true,
 	258:  true,
+	263:  true,
+	264:  true,
 	268:  true,
 	283:  true,
 	290:  true,

problems/ugly-number-ii/ugly_number_ii.go

@@ -1 +1,19 @@
 package problem264
+
+func nthUglyNumber(n int) int {
+	ans, idx := make([]int, n), [3]int{}
+	ans[0] = 1
+	for i := 1; i < n; i++ {
+		for j, n := range [...]int{2, 3, 5} {
+			if ans[idx[j]]*n <= ans[i-1] {
+				idx[j]++
+			}
+			if num := ans[idx[j]] * n; j == 0 {
+				ans[i] = num
+			} else if ans[i] > num {
+				ans[i] = num
+			}
+		}
+	}
+	return ans[n-1]
+}

problems/ugly-number-ii/ugly_number_ii_test.go

@@ -1 +1,39 @@
 package problem264
+
+import "testing"
+
+type caseType struct {
+	input    int
+	expected int
+}
+
+func TestNthUglyNumber(t *testing.T) {
+	tests := [...]caseType{
+		{
+			input:    10,
+			expected: 12,
+		},
+		{
+			input:    9,
+			expected: 10,
+		},
+		{
+			input:    60,
+			expected: 384,
+		},
+		{
+			input:    90,
+			expected: 1152,
+		},
+		{
+			input:    1,
+			expected: 1,
+		},
+	}
+	for _, tc := range tests {
+		output := nthUglyNumber(tc.input)
+		if output != tc.expected {
+			t.Fatalf("input: %v, output: %v, expected: %v", tc.input, output, tc.expected)
+		}
+	}
+}