代码均为自己手写,如有错误或更优解法,劳烦小伙伴们指教哈~
1、斐波那契数列
// 解法一
function a (n, a1 = 1, a2 = 1) {
if (n <= 1) return a1
return a(n - 1, a2, a1 + a2)
}
let res = a(5)
console.log(res)
// 解法二
let a1 = 1, a2 = 1
function b (n) {
if (n <= 1) return a
for (let i = 0; i < (n - 2); i++) {
let t = a2
a2 = a1 + a2
a1 = t
}
return a2
}
let res = b(5)
console.log(res)
2、冒泡排序
let arr = [2, 53, 32, 21, 432, 54, 76, 45, 654]
let l = arr.length
for (let i = 0; i < arr.length; i++) {
for (let j = l - 1; j >= i; j--) {
if (arr[j] > arr[j - 1]) {
let t = arr[j]
arr[j] = arr[j - 1]
arr[j - 1] = t
}
}
}
console.log(arr)
3、选择排序
let arr = [2, 53, 32, 21, 432, 54, 76, 45, 654]
let l = arr.length
for (let i = 0; i < l; i++) {
let min = arr[i]
let index = i
for (let j = i; j < l; j++) {
if (arr[j] < min) {
min = arr[j]
index = j
}
}
if (index !== i) {
arr[index] = arr[i]
arr[i] = min
}
}
console.log(arr)
4、插入排序
let arr = [2, 53, 32, 21, 432, 54, 76, 45, 654]
let l = arr.length
for (let i = 0; i < l; i++) {
let index = i
while (index >= 1 && arr[index] < arr[index - 1]) {
let t = arr[index]
arr[index] = arr[index - 1]
arr[index - 1] = t
index --
}
}
console.log(arr)
5、希尔排序
let arr = [2, 53, 32, 21, 432, 54, 76, 45, 654]
let l = arr.length
let gap = Math.floor(l / 2)
for (gap; gap > 0; gap = Math.floor(gap / 2)) {
for (let i = gap; i < l; i++) {
let t = arr[i]
let index = -1
for (let j = i - gap; j > 0 && arr[j] > t; j -= gap) {
arr[j + gap] = arr[j]
index = j
}
if (index !== -1) {
arr[index] = t
}
}
}
console.log(arr)
7、快速排序
let arr = [89, 53, 32, 21, 432, 54, 76, 45, 654]
function quickSort (arr, left, right) {
if (left >= right) {
return
}
let i = left, j = right
// 记录当前基准值在左边还是右边
let flag = 'left'
while (i < j) {
if (flag === 'left') {
while (arr[i] < arr[j]) {
j --
}
if (i < j) {
let tmp = arr[i]
arr[i] = arr[j]
arr[j] = tmp
flag = 'right'
i ++
}
} else if (flag === 'right') {
while (arr[i] < arr[j]) {
i ++
}
if (i < j) {
let tmp = arr[i]
arr[i] = arr[j]
arr[j] = tmp
flag = 'left'
j --
}
}
}
quickSort(arr, left, i - 1)
quickSort(arr, i + 1, right)
}
quickSort(arr, 0, arr.length - 1)
console.log(arr)
持续更新中...