// File: climbing_stairs_dp.go // Created Time: 2023-07-18 // Author: Reanon (793584285@qq.com) package chapter_dynamic_programming /* Climbing stairs: Dynamic programming */ func climbingStairsDP(n int) int { if n == 1 || n == 2 { return n } // Initialize dp table, used to store subproblem solutions dp := make([]int, n+1) // Initial state: preset the smallest subproblem solution dp[1] = 1 dp[2] = 2 // State transition: gradually solve larger subproblems from smaller ones for i := 3; i <= n; i++ { dp[i] = dp[i-1] + dp[i-2] } return dp[n] } /* Climbing stairs: Space-optimized dynamic programming */ func climbingStairsDPComp(n int) int { if n == 1 || n == 2 { return n } a, b := 1, 2 // State transition: gradually solve larger subproblems from smaller ones for i := 3; i <= n; i++ { a, b = b, a+b } return b }