Given an array of integers?arr, return?true?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?(arr[0] + arr[1] + ... + arr[i] == arr[i + 1] + arr[i + 2] + ... + arr[j - 1] == arr[j] + arr[j + 1] + ... + arr[arr.length - 1])

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Example 1:

Input: arr = [0,2,1,-6,6,-7,9,1,2,0,1]Output: trueExplanation: 0 + 2 + 1 = -6 + 6 - 7 + 9 + 1 = 2 + 0 + 1

Example 2:

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

Example 3:

Input: arr = [3,3,6,5,-2,2,5,1,-9,4]Output: trueExplanation: 3 + 3 = 6 = 5 - 2 + 2 + 5 + 1 - 9 + 4

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Constraints:

• 3 <= arr.length <= 5 * 104

• -104?<= arr[i] <= 104

Easy 題目，少考慮了一件事情，就是分3份，分完了還剩下一些，怎么辦，就是直接累加是否等于0，即可；

Runtime:?3 ms, faster than?32.14%?of?Java?online submissions for?Partition Array Into Three Parts With Equal Sum.

Memory Usage:?50 MB, less than?87.32%?of?Java?online submissions for?Partition Array Into Three Parts With Equal Sum.