mirror of
https://github.com/krahets/hello-algo.git
synced 2024-12-26 00:56:29 +08:00
a005c6ebd3
* Update avatar's link in the landing page * Bug fixes * Move assets folder from overrides to docs * Reduce figures' corner radius * Update copyright * Update header image * Krahets -> krahets * Update the landing page
48 lines
1.5 KiB
Python
48 lines
1.5 KiB
Python
"""
|
|
File: coin_change_greedy.py
|
|
Created Time: 2023-07-18
|
|
Author: krahets (krahets@163.com)
|
|
"""
|
|
|
|
|
|
def coin_change_greedy(coins: list[int], amt: int) -> int:
|
|
"""零钱兑换：贪心"""
|
|
# 假设 coins 列表有序
|
|
i = len(coins) - 1
|
|
count = 0
|
|
# 循环进行贪心选择，直到无剩余金额
|
|
while amt > 0:
|
|
# 找到小于且最接近剩余金额的硬币
|
|
while i > 0 and coins[i] > amt:
|
|
i -= 1
|
|
# 选择 coins[i]
|
|
amt -= coins[i]
|
|
count += 1
|
|
# 若未找到可行方案，则返回 -1
|
|
return count if amt == 0 else -1
|
|
|
|
|
|
"""Driver Code"""
|
|
if __name__ == "__main__":
|
|
# 贪心：能够保证找到全局最优解
|
|
coins = [1, 5, 10, 20, 50, 100]
|
|
amt = 186
|
|
res = coin_change_greedy(coins, amt)
|
|
print(f"\ncoins = {coins}, amt = {amt}")
|
|
print(f"凑到 {amt} 所需的最少硬币数量为 {res}")
|
|
|
|
# 贪心：无法保证找到全局最优解
|
|
coins = [1, 20, 50]
|
|
amt = 60
|
|
res = coin_change_greedy(coins, amt)
|
|
print(f"\ncoins = {coins}, amt = {amt}")
|
|
print(f"凑到 {amt} 所需的最少硬币数量为 {res}")
|
|
print(f"实际上需要的最少数量为 3 ，即 20 + 20 + 20")
|
|
|
|
# 贪心：无法保证找到全局最优解
|
|
coins = [1, 49, 50]
|
|
amt = 98
|
|
res = coin_change_greedy(coins, amt)
|
|
print(f"\ncoins = {coins}, amt = {amt}")
|
|
print(f"凑到 {amt} 所需的最少硬币数量为 {res}")
|
|
print(f"实际上需要的最少数量为 2 ，即 49 + 49")
|