# 1020. Number of Enclaves 飞地的数量

@TOC

## # 题目描述

Given an array `A` of integers, return `true` if and only if we can partition the array into three non-empty parts with equal sums.

Formally, we can partition the array if we can find indexes `i+1 < j` with `(A[0] + A[1] + ... + A[i] == A[i+1] + A[i+2] + ... + A[j-1] == A[j] + A[j-1] + ... + A[A.length - 1])`

Example 1:

``````Input: [0,2,1,-6,6,-7,9,1,2,0,1]
Output: true
Explanation: 0 + 2 + 1 = -6 + 6 - 7 + 9 + 1 = 2 + 0 + 1
``````

Example 2:

``````Input: [0,2,1,-6,6,7,9,-1,2,0,1]
Output: false
``````

Example 3:

``````Input: [3,3,6,5,-2,2,5,1,-9,4]
Output: true
Explanation: 3 + 3 = 6 = 5 - 2 + 2 + 5 + 1 - 9 + 4
``````

Note:

1. 3 <= A.length <= 50000
2. -10000 <= A[i] <= 10000

## # 解题方法

Python代码如下：

``````class Solution(object):
def canThreePartsEqualSum(self, A):
"""
:type A: List[int]
:rtype: bool
"""
_sum = sum(A)
if _sum % 3 != 0:
return False
target = _sum / 3
count = 0
cursum = 0
for a in A:
cursum += a
if cursum == target:
count += 1
cursum = 0
return count >= 3
``````

## # 日期

2019 年 3 月 24 日 —— 这个周赛太悲催了