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This article mainly shows you how to solve the problem of exchanging numbers and three steps in golang brush leetcode skills. The content is simple and easy to understand and the organization is clear. I hope it can help you solve your doubts. Let Xiaobian lead you to study and learn this article "how to solve the problem of exchanging numbers and three steps in golang brush leetcode skills."

Write a function that swaps the values of a and b in numbers = [a, b] without temporary variables.

Examples:

Input: numbers = [1,2]

Output: [2,1]

Tip:

numbers.length == 2

Solution:

Method 1:

summing

Method 2:

XOR

Code implementation:

func swapNumbers(numbers []int) []int { numbers[0]+=numbers[1] numbers[1]=numbers[0]-numbers[1] numbers[0]-=numbers[1] return numbers}func swapNumbers(numbers []int) []int { numbers[0]^=numbers[1] numbers[1]=numbers[0]^numbers[1] numbers[0]^=numbers[1] return numbers}

Three step problem. A child is climbing a staircase. The staircase has n steps. The child can climb one, two or three steps at a time. Implement a method to calculate how many ways a child can climb stairs. The result may be very large, you need to modulo 10000007 for the result.

Example 1:

Input: n = 3

Output: 4

Description: There are four ways to go

Example 2:

Input: n = 5

Output: 13

Tip:

n ranges between [1, 1000000]

Solution:

1, recursion

To reach step n, it can be 3 steps from step n-3, 2 steps from step n-2, or 1 step from step n-1.

2，dp

State transition equation, f (n)=f(n-3)+f(n-2)+f(n-1)

Since we're using n-3,n-2, n-1, the incremental approach

func waysToStep(n int) int { if n==1{ return 1 } if n==2{ return 2 } if n==3{ return 4 } return (waysToStep(n-3)+waysToStep(n-2)+waysToStep(n-1))00000007}func waysToStep(n int) int { dp:=make([]int,n) if n==1{ return 1 } if n==2{ return 2 } if n==3{ return 4 } dp[0]=1 dp[1]=2 dp[2]=4 for i:=3;i

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