def knapsack_01(weights, values, W):
n = len(weights)
dp = [[0] * (W + 1) for _ in range(n + 1)]
for i in range(1, n + 1):
for j in range(1, W + 1):
if weights[i - 1] > j:
dp[i][j] = dp[i - 1][j]
else:
dp[i][j] = max(dp[i - 1][j], dp[i - 1][j - weights[i - 1]] + values[i - 1])
return dp[n][W]
weights = [2, 1, 3, 2]
values = [12, 10, 20, 15]
max_weight = 5
result = knapsack_01(weights, values, max_weight)
print(f"最大的值是: {result}")