Package g0701_0800.s0724_find_pivot_index

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    724 - Find Pivot Index\.

    Easy

    Given an array of integers nums, calculate the pivot index of this array.

    The pivot index is the index where the sum of all the numbers strictly to the left of the index is equal to the sum of all the numbers strictly to the index's right.

    If the index is on the left edge of the array, then the left sum is 0 because there are no elements to the left. This also applies to the right edge of the array.

    Return the leftmost pivot index. If no such index exists, return -1.

    Example 1:

    Input: nums = 1,7,3,6,5,6

    Output: 3

    Explanation: The pivot index is 3. Left sum = nums0 + nums1 + nums2 = 1 + 7 + 3 = 11 Right sum = nums4 + nums5 = 5 + 6 = 11

    Example 2:

    Input: nums = 1,2,3

    Output: -1

    Explanation: There is no index that satisfies the conditions in the problem statement.

    Example 3:

    Input: nums = 2,1,-1

    Output: 0

    Explanation: The pivot index is 0. Left sum = 0 (no elements to the left of index 0) Right sum = nums1 + nums2 = 1 + -1 = 0

    Constraints:

    • <code>1 <= nums.length <= 10<sup>4</sup></code>

    • -1000 &lt;= nums[i] &lt;= 1000

    Note: This question is the same as 1991: https://leetcode.com/problems/find-the-middle-index-in-array/

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description

    • Method Summary

      Modifier and Type Method Description
      final Integer pivotIndex(IntArray nums)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait