Given an array A
of 0
s and 1
s, divide the array into 3 non-empty parts such that all of these parts represent the same binary value.
If it is possible, return any [i, j]
with i+1 < j
, such that:
A[0], A[1], ..., A[i]
is the first part;A[i+1], A[i+2], ..., A[j-1]
is the second part, andA[j], A[j+1], ..., A[A.length - 1]
is the third part.- All three parts have equal binary value.
If it is not possible, return [-1, -1]
.
Note that the entire part is used when considering what binary value it represents. For example, [1,1,0]
represents 6
in decimal, not 3
. Also, leading zeros are allowed, so [0,1,1]
and [1,1]
represent the same value.
Example 1:
Input: [1,0,1,0,1]
Output: [0,3]
Example 2:
Input: [1,1,0,1,1]
Output: [-1,-1]
Note:
3 <= A.length <= 30000
A[i] == 0
orA[i] == 1
给定一个由 0
和 1
组成的数组 A
,将数组分成 3 个非空的部分,使得所有这些部分表示相同的二进制值。
如果可以做到,请返回任何 [i, j]
,其中 i+1 < j
,这样一来:
A[0], A[1], ..., A[i]
组成第一部分;A[i+1], A[i+2], ..., A[j-1]
作为第二部分;A[j], A[j+1], ..., A[A.length - 1]
是第三部分。- 这三个部分所表示的二进制值相等。
如果无法做到,就返回 [-1, -1]
。
注意,在考虑每个部分所表示的二进制时,应当将其看作一个整体。例如,[1,1,0]
表示十进制中的 6
,而不会是 3
。此外,前导零也是被允许的,所以 [0,1,1]
和 [1,1]
表示相同的值。
示例 1:
输入:[1,0,1,0,1] 输出:[0,3]
示例 2:
输出:[1,1,0,1,1] 输出:[-1,-1]
提示:
3 <= A.length <= 30000
A[i] == 0
或A[i] == 1
428ms
1 class Solution { 2 func threeEqualParts(_ A: [Int]) -> [Int] { 3 let countA:Int = A.count 4 var one:Int = 0 5 for x in A {one += x} 6 if one % 3 != 0 {return [-1,-1]} 7 if one == 0 {return [0,countA - 1]} 8 one /= 3 9 var cc:Int = 0 10 var pos:[Int] = [Int](repeating: -2,count: 3) 11 var idx:Int = 0 12 for i in 0..<countA 13 { 14 if A[i] == 1 && cc % one == 0 15 { 16 pos[idx] = i 17 idx += 1 18 } 19 cc += A[i] 20 } 21 var len:Int = countA - pos[2] 22 if pos[1] < (pos[0] + len) || pos[2] < (pos[1] + len) {return [-1,-1]} 23 var i:Int = pos[0], j:Int = pos[1], k:Int = pos[2] 24 repeat 25 { 26 if (A[i] != A[j] || A[i] != A[k]) {return [-1,-1]}; 27 i += 1 28 j += 1 29 k += 1 30 }while(k < countA) 31 return [pos[0] + len - 1, pos[1] + len] 32 } 33 }