add: 只出现一次的数字等

test/math/coin-lcci.test.js

@@ -0,0 +1,6 @@
+import { waysToChange } from '../../src/math/coin-lcci'
+
+test('硬币', () => {
+  expect(waysToChange(5)).toBe(2)
+  expect(waysToChange(10)).toBe(4)
+})

test/math/factorial-trailing-zeroes.test.js

@@ -0,0 +1,6 @@
+import trailingZeroes from '../../src/math/factorial-trailing-zeroes'
+
+test('trailingZeroes', () => {
+  expect(trailingZeroes(3)).toBe(0)
+  expect(trailingZeroes(5)).toBe(1)
+})

test/math/permutations.test.js

@@ -0,0 +1,12 @@
+import { permute } from '../../src/math/permutations'
+
+test('全排列', () => {
+  expect(permute([1, 2, 3])).toEqual([
+    [1, 2, 3],
+    [1, 3, 2],
+    [2, 1, 3],
+    [2, 3, 1],
+    [3, 1, 2],
+    [3, 2, 1]
+  ])
+})

test/math/ugly-number-ii.test.js

@@ -0,0 +1,7 @@
+import { nthUglyNumber } from '../../src/math/ugly-number-ii.js'
+
+test('丑数 II', () => {
+  expect(nthUglyNumber(9)).toBe(10)
+  expect(nthUglyNumber(1)).toBe(1)
+  expect(nthUglyNumber(10)).toBe(12)
+})