add python code

public/py/ch4/money/coin_change.py

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+"""
+找零问题 — 贪心算法
+使用最少硬币凑出指定金额
+"""
+
+def min_coins_greedy(coins, amount):
+    """贪心找零（硬币面额需满足贪心选择性质）"""
+    coins_sorted = sorted(coins, reverse=True)
+    result = []
+    remaining = amount
+
+    for coin in coins_sorted:
+        while remaining >= coin:
+            result.append(coin)
+            remaining -= coin
+
+    return result
+
+def min_coins_dp(coins, amount):
+    """动态规划找零（通用解法）"""
+    MAX = float('inf')
+    dp = [MAX] * (amount + 1)
+    dp[0] = 0
+
+    for i in range(1, amount + 1):
+        for coin in coins:
+            if i >= coin:
+                dp[i] = min(dp[i], dp[i - coin] + 1)
+
+    return dp[amount] if dp[amount] != MAX else -1
+
+if __name__ == "__main__":
+    coins = [1, 5, 10, 25]
+    amount = 63
+
+    greedy_result = min_coins_greedy(coins, amount)
+    dp_result = min_coins_dp(coins, amount)
+
+    print(f"硬币面额: {coins}")
+    print(f"需要凑出: {amount}")
+    print(f"贪心结果: {greedy_result} (共 {len(greedy_result)} 枚)")
+    print(f"DP最少数量: {dp_result} 枚")