leetcode-312-戳气球

题目描述：

 

 

 

官方解答：

 方法一：记忆化递归 O(N³) O(N²)

class Solution:
    def maxCoins(self, nums: List[int]) -> int:
        n = len(nums)
        val = [1] + nums + [1]
        
        @lru_cache(None)
        def solve(left: int, right: int) -> int:
            if left >= right - 1:
                return 0
            
            best = 0
            for i in range(left + 1, right):
                total = val[left] * val[i] * val[right]
                total += solve(left, i) + solve(i, right)
                best = max(best, total)
            
            return best

        return solve(0, n + 1)

作者：LeetCode-Solution
链接：https://leetcode-cn.com/problems/burst-balloons/solution/chuo-qi-qiu-by-leetcode-solution/
来源：力扣（LeetCode）
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

方法二：动态规划 O(N³) O(N²)

class Solution:
    def maxCoins(self, nums: List[int]) -> int:
        n = len(nums)
        rec = [[0] * (n + 2) for _ in range(n + 2)]
        val = [1] + nums + [1]

        for i in range(n - 1, -1, -1):
            for j in range(i + 2, n + 2):
                for k in range(i + 1, j):
                    total = val[i] * val[k] * val[j]
                    total += rec[i][k] + rec[k][j]
                    rec[i][j] = max(rec[i][j], total)
        
        return rec[0][n + 1]

作者：LeetCode-Solution
链接：https://leetcode-cn.com/problems/burst-balloons/solution/chuo-qi-qiu-by-leetcode-solution/
来源：力扣（LeetCode）
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。