diff --git a/problems/0343.整数拆分.md b/problems/0343.整数拆分.md index fefaa293..cf60575f 100644 --- a/problems/0343.整数拆分.md +++ b/problems/0343.整数拆分.md @@ -218,7 +218,7 @@ class Solution: # 假设对正整数 i 拆分出的第一个正整数是 j(1 <= j < i),则有以下两种方案: # 1) 将 i 拆分成 j 和 i−j 的和,且 i−j 不再拆分成多个正整数,此时的乘积是 j * (i-j) # 2) 将 i 拆分成 j 和 i−j 的和,且 i−j 继续拆分成多个正整数,此时的乘积是 j * dp[i-j] - for j in range(1, i): + for j in range(1, i - 1): dp[i] = max(dp[i], max(j * (i - j), j * dp[i - j])) return dp[n] ``` diff --git a/problems/背包理论基础01背包-1.md b/problems/背包理论基础01背包-1.md index 852c489b..1269d9c1 100644 --- a/problems/背包理论基础01背包-1.md +++ b/problems/背包理论基础01背包-1.md @@ -268,7 +268,7 @@ int main() { Java: ```java - public static void main(String[] args) { + public static void main(String[] args) { int[] weight = {1, 3, 4}; int[] value = {15, 20, 30}; int bagSize = 4; @@ -307,6 +307,41 @@ Java: Python: +```python +def test_2_wei_bag_problem1(bag_size, weight, value) -> int: + rows, cols = len(weight), bag_size + 1 + dp = [[0 for _ in range(cols)] for _ in range(rows)] + res = 0 + + # 初始化dp数组. + for i in range(rows): + dp[i][0] = 0 + first_item_weight, first_item_value = weight[0], value[0] + for j in range(1, cols): + if first_item_weight <= j: + dp[0][j] = first_item_value + + # 更新dp数组: 先遍历物品, 再遍历背包. + for i in range(1, len(weight)): + cur_weight, cur_val = weight[i], value[i] + for j in range(1, cols): + if cur_weight > j: # 说明背包装不下当前物品. + dp[i][j] = dp[i - 1][j] # 所以不装当前物品. + else: + # 定义dp数组: dp[i][j] 前i个物品里,放进容量为j的背包,价值总和最大是多少。 + dp[i][j] = max(dp[i - 1][j], dp[i - 1][j - cur_weight]+ cur_val) + if dp[i][j] > res: + res = dp[i][j] + + print(dp) + + +if __name__ == "__main__": + bag_size = 4 + weight = [1, 3, 4] + value = [15, 20, 30] + test_2_wei_bag_problem1(bag_size, weight, value) +``` Go: