Skip to main content

9. Majority Element

easyAsked at Freshworks

Find the agent ID assigned to more than half the open tickets — a Boyer-Moore voting drill that Freshworks dresses up as automation-rule triage.

By Alex Chen, Founder, InterviewChamp.AI · Last verified

Problem

Given an array nums of size n, return the majority element — the element that appears more than n/2 times. You may assume a majority element always exists.

Constraints

  • 1 <= n <= 5 * 10^4
  • Majority element is guaranteed
  • Solve in linear time and constant space

Examples

Example 1

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

Example 2

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

Approaches

1. Brute force with Map

Count each element and return the one with count > n/2.

Time
O(n)
Space
O(n)
const m = new Map();
for (const x of nums) m.set(x, (m.get(x)||0)+1);
for (const [k,v] of m) if (v > nums.length/2) return k;

Tradeoff:

2. Boyer-Moore voting

Track a candidate and a count. On match, count++. On mismatch, count--. When count hits 0, swap the candidate. Survivor is the majority.

Time
O(n)
Space
O(1)
function majorityElement(nums) {
  let candidate = null, count = 0;
  for (const n of nums) {
    if (count === 0) candidate = n;
    count += (n === candidate) ? 1 : -1;
  }
  return candidate;
}

Tradeoff:

Freshworks-specific tips

Freshworks wants Boyer-Moore by name — say 'voting algorithm' explicitly and justify why the candidate survives because the majority outvotes everyone else combined.

Solve it now

Free. No sign-up. Python and JavaScript run instantly in your browser.

Output

Press Run or Cmd+Enter to execute

Practice these live with InterviewChamp.AI

Drill Majority Element and other Freshworks interview questions under real-loop conditions with instant feedback on your reasoning, complexity claims, and code.

Practice these live with InterviewChamp.AI →