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Update the text and code of DP.

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krahets
2023-07-10 20:36:48 +08:00
parent 5ea016816a
commit 465dafe9ec
5 changed files with 24 additions and 21 deletions
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14
codes/python/chapter_dynamic_programming/knapsack.py
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@ -52,7 +52,7 @@ def knapsack_dp(wgt, val, cap):
dp[i][c] = dp[i - 1][c]
else:
# 不选和选物品 i 这两种方案的较大值
dp[i][c] = max(dp[i - 1][c - wgt[i - 1]] + val[i - 1], dp[i - 1][c])
dp[i][c] = max(dp[i - 1][c], dp[i - 1][c - wgt[i - 1]] + val[i - 1])
return dp[n][cap]
@ -70,30 +70,30 @@ def knapsack_dp_comp(wgt, val, cap):
dp[c] = dp[c]
else:
# 不选和选物品 i 这两种方案的较大值
dp[c] = max(dp[c - wgt[i - 1]] + val[i - 1], dp[c])
dp[c] = max(dp[c], dp[c - wgt[i - 1]] + val[i - 1])
return dp[cap]
"""Driver Code"""
if __name__ == "__main__":
wgt = [10, 20, 30, 40, 50]
val = [60, 100, 120, 160, 200]
val = [50, 120, 150, 210, 240]
cap = 50
n = len(wgt)
# 暴力搜索
res = knapsack_dfs(wgt, val, n, cap)
print(res)
print(f"不超过背包容量的最大物品价值为 {res}")
# 记忆化搜索
mem = [[-1] * (cap + 1) for _ in range(n + 1)]
res = knapsack_dfs_mem(wgt, val, mem, n, cap)
print(res)
print(f"不超过背包容量的最大物品价值为 {res}")
# 动态规划
res = knapsack_dp(wgt, val, cap)
print(res)
print(f"不超过背包容量的最大物品价值为 {res}")
# 状态压缩后的动态规划
res = knapsack_dp_comp(wgt, val, cap)
print(res)
print(f"不超过背包容量的最大物品价值为 {res}")