mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-26 02:06:30 +08:00
3f4220de81
* preorder, inorder, postorder -> pre-order, in-order, post-order * Bug fixes * Bug fixes * Update what_is_dsa.md * Sync zh and zh-hant versions * Sync zh and zh-hant versions. * Update performance_evaluation.md and time_complexity.md * Add @khoaxuantu to the landing page. * Sync zh and zh-hant versions * Add @ khoaxuantu to the landing page of zh-hant and en versions.
63 lines
1.5 KiB
Ruby
63 lines
1.5 KiB
Ruby
=begin
|
||
File: coin_change_ii.rb
|
||
Created Time: 2024-05-29
|
||
Author: Xuan Khoa Tu Nguyen (ngxktuzkai2000@gmail.com)
|
||
=end
|
||
|
||
### 零錢兌換 II：動態規劃 ###
|
||
def coin_change_ii_dp(coins, amt)
|
||
n = coins.length
|
||
# 初始化 dp 表
|
||
dp = Array.new(n + 1) { Array.new(amt + 1, 0) }
|
||
# 初始化首列
|
||
(0...(n + 1)).each { |i| dp[i][0] = 1 }
|
||
# 狀態轉移
|
||
for i in 1...(n + 1)
|
||
for a in 1...(amt + 1)
|
||
if coins[i - 1] > a
|
||
# 若超過目標金額，則不選硬幣 i
|
||
dp[i][a] = dp[i - 1][a]
|
||
else
|
||
# 不選和選硬幣 i 這兩種方案之和
|
||
dp[i][a] = dp[i - 1][a] + dp[i][a - coins[i - 1]]
|
||
end
|
||
end
|
||
end
|
||
dp[n][amt]
|
||
end
|
||
|
||
### 零錢兌換 II：空間最佳化後的動態規劃 ###
|
||
def coin_change_ii_dp_comp(coins, amt)
|
||
n = coins.length
|
||
# 初始化 dp 表
|
||
dp = Array.new(amt + 1, 0)
|
||
dp[0] = 1
|
||
# 狀態轉移
|
||
for i in 1...(n + 1)
|
||
# 正序走訪
|
||
for a in 1...(amt + 1)
|
||
if coins[i - 1] > a
|
||
# 若超過目標金額，則不選硬幣 i
|
||
dp[a] = dp[a]
|
||
else
|
||
# 不選和選硬幣 i 這兩種方案之和
|
||
dp[a] = dp[a] + dp[a - coins[i - 1]]
|
||
end
|
||
end
|
||
end
|
||
dp[amt]
|
||
end
|
||
|
||
### Driver Code ###
|
||
if __FILE__ == $0
|
||
coins = [1, 2, 5]
|
||
amt = 5
|
||
|
||
# 動態規劃
|
||
res = coin_change_ii_dp(coins, amt)
|
||
puts "湊出目標金額的硬幣組合數量為 #{res}"
|
||
|
||
# 空間最佳化後的動態規劃
|
||
res = coin_change_ii_dp_comp(coins, amt)
|
||
puts "湊出目標金額的硬幣組合數量為 #{res}"
|
||
end
|