Missing Number Easy 0 attempts
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Missing Number

Easy MatrixBFSDFS LeetCode

You're given an array nums holding n distinct integers, with every value falling somewhere in the inclusive range [0, n]. Out of all the integers in that range, exactly one does not appear in the array — figure out which one and return it.

The complete range spans n + 1 values, {0, 1, …, n}, while the array only holds n of them.

Input Format
Implement missingNumber(nums). Inputs below show JavaScript function arguments; there is no stdin parsing.
Output Format
Return the result described in the statement.

Sample Input and Output

Example 1 · Run Sample

Input
nums = [3,0,1]
Output
2

Example 2

Input
nums = [0,1]
Output
2

Example 3

Input
nums = [9,6,4,2,3,5,7,0,1]
Output
8
Constraints
  • n == nums.length
  • 1 <= n <= 10^4
  • 0 <= nums[i] <= n
  • All numbers are unique
Test Cases (3)
Case 1
Args: [[3,0,1]] Expected: 2
Case 2
Args: [[0,1]] Expected: 2
Case 3
Args: [[9,6,4,2,3,5,7,0,1]] Expected: 8
Topics
MatrixBFSDFS

XOR or Math

javascript
function missingNumber(nums) {
  const n = nums.length;
  return n * (n + 1) / 2 - nums.reduce((a, b) => a + b, 0);
}

Time: O(n) | Space: O(1)

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JavaScript