You are given an integer array nums. A tuple (i, j, k) of 3 distinct indices is good if nums[i] == nums[j] == nums[k]. The distance of a good tuple is abs(i - j) + abs(j - k) + abs(k - i), where abs(x) denotes the absolute value of x. Return an in

minimumDistance.js

/**
 * @param {number[]} nums
 * @return {number}
 */
var minimumDistance = function(nums) {
    const lastTwo = new Map(); // value -> [prevPrev, prev]
    let ans = Infinity;

    for (let i = 0; i < nums.length; i++) {
        const v = nums[i];

        if (!lastTwo.has(v)) {
            lastTwo.set(v, [i]); // first occurrence
            continue;
        }

        const arr = lastTwo.get(v);

        if (arr.length === 1) {
            // second occurrence
            arr.push(i);
            continue;
        }

        // arr.length === 2 → we have a triple window
        const [a, b] = arr; // previous two
        const c = i;        // current

        ans = Math.min(ans, 2 * (c - a));

        // slide window:drop oldest, keep newest two
        lastTwo.set(v, [b, c]);
    }

    return ans === Infinity ? -1 : ans;
};