我的解答:
代码语言：javascript复制class Solution:
def threeEqualParts(self, arr: list[int]) -> list[int]:
n = len(arr)
if n < 3: return [-1, -1]
s = sum(arr) # arr 中 1的个数
if s % 3 != 0: return [-1, -1] # 1 的个数不能被3整除则无解
if s == 0 and len(arr) >= 3: return [0, 2]
m = s//3 # qty of ones in each
flag = True
s1 = 0
for i in range(n):
if arr[i] != 0:
s1 = 1
if flag:
ones1_left = i
flag = False
if s1 == m:
ones1_right = i
break
flag = True
s2 = 0
for j in range(i 1, n):
if arr[j] != 0:
s2 = 1
if flag:
ones2_left = j
flag = False
if s2 == m:
ones2_right = j
break
flag = True
s3 = 0
for k in range(j 1, n):
if arr[k] != 0:
s3 = 1
if flag:
ones3_left = k
flag = False
if s3 == m:
ones3_right = k
break
right_side_zeros = n - (ones3_right 1) # 最后一组末尾的0的个数
# print(right_side_zeros)
if ones2_left < ones1_right right_side_zeros 1 or ones3_left < ones2_right right_side_zeros 1:
return [-1, -1]
i = ones1_right right_side_zeros
a1 = arr[ones1_left: i 1]
if n < 3 * len(a1):
return [-1,-1]
j = ones2_right right_side_zeros 1
if (j-i-1) < len(a1) or (n-j) < len(a1): # a2 或 a3 的可能的最大长度不能小于a1的长度
return [-1,-1]
a2 = arr[ones2_left: j]
if a1 != a2:
return [-1,-1]
a3 = arr[ones3_left:]
if a1 == a3:
return [i,j]
return [-1,-1]
