diff --git a/problems/0377.组合总和Ⅳ.md b/problems/0377.组合总和Ⅳ.md index d9699c54..05f852b1 100644 --- a/problems/0377.组合总和Ⅳ.md +++ b/problems/0377.组合总和Ⅳ.md @@ -206,6 +206,34 @@ class Solution: ``` +二维DP版 +```python +class Solution: + def combinationSum4(self, nums: List[int], target: int) -> int: + # dp[][j]和为j的组合的总数 + dp = [[0] * (target+1) for _ in nums] + + for i in range(len(nums)): + dp[i][0] = 1 + + # 这里不能初始化dp[0][j]。dp[0][j]的值依赖于dp[-1][j-nums[0]] + + for j in range(1, target+1): + for i in range(len(nums)): + + if j - nums[i] >= 0: + dp[i][j] = ( + # 不放nums[i] + # i = 0 时,dp[-1][j]恰好为0,所以没有特殊处理 + dp[i-1][j] + + # 放nums[i]。对于和为j的组合,只有试过全部物品,才能知道有几种组合方式。所以取最后一个物品dp[-1][j-nums[i]] + dp[-1][j-nums[i]] + ) + else: + dp[i][j] = dp[i-1][j] + return dp[-1][-1] +``` + ### Go: ```go