python-leetcode题解之第1013题将数组分成和相等的三个部分.zip

''' 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: 3 <= A.length <= 50000 -10000 <= A[i] <= 10000 ''' class Solution(object): def canThreePartsEqualSum(self, A): """ :type A: List[int] :rtype: bool """ total_sum = 0 for val in A: total_sum += val if(total_sum%3 != 0): return False curr_sum, groups = 0, 0 for val in A: curr_sum += val if curr_sum == total_sum/3: curr_sum = 0 groups +=1 print groups return groups == 3