题目
You are given an integer array nums and an integer x. In one operation, you can either remove the leftmost or the rightmost element from the array nums and subtract its value from x. Note that this modifies the array for future operations.
Return the minimum number of operations to reduce x to exactly 0 if it’s possible, otherwise, return -1.
解题思路
题目相当于求一个最长的连续子数组，和为sum-x，使用两个指针，通过滑动窗口找到最长的子数组
代码
class Solution:
def minOperations(self, nums: List[int], x: int) -> int:
target = sum(nums) - x
if target == 0:
return len(nums)
if target < 0:
return -1
l, r, window = 0, 0, 0
max_len = -1
while r < len(nums):
window += nums[r]
r += 1
while window >= target:
if (window == target):
max_len = max(max_len, r - l)
window -= nums[l]
l += 1
return -1 if max_len == -1 else len(nums) - max_len
