基础算法汇总

1.链表翻转

func (n *node) reverse() *node {
	var res *node
	cur := n
	var pre *node
	for {
		next := cur.next
		cur.next = pre
		pre = cur
		cur = next
		if cur == nil {
			return pre
		}
	}
	return res
}

2.爬楼梯

func climbStairs(n int) int {
	n1,n2,num :=0,0,1
	for i:=1;i<=n;i++{
		n1 = n2
		n2 = num
		num = n1+n2
	}
	return num
}

3.冒泡法

func bubbleSort(arr []int) {
	for i := 0; i < len(arr)-1; i++ {
		for j := 0; j < len(arr)-i-1; j++ {
			if arr[j] > arr[j+1] {
				arr[j], arr[j+1] = arr[j+1], arr[j]
			}
		}
	}
}

4.快速排序法

func quickSort(arr []int) []int {
	if len(arr) <= 1 {return arr}
	middleValue := arr[0]
	left, right := []int{}, []int{}
	for _, num := range arr[1:] {
		if num <= middleValue {
			left = append(left, num)
		} else {
			right = append(right, num)
		}
	}
	leftSorted := quickSort(left)
	rightSorted := quickSort(right)
	result := make([]int, len(leftSorted)+len(rightSorted)+1)
	copy(result, leftSorted)// 复制左子数组到结果切片
	result[len(leftSorted)] = middleValue
	copy(result[len(leftSorted)+1:], rightSorted)	// 复制右子数组到结果切片
	return result
}

5.二分查找法

func BinarySearch(arr []int, target int) int {
	left, right := 0, len(arr)-1
	for left <= right {
		mid := left + (right-left)/2
		if arr[mid] == target {
			return mid
		} else if arr[mid] < target {
			left = mid + 1
		} else {
			right = mid - 1
		}
	}
	return -1