You have n computers. You are given the integer n and a 0-indexed integer array batteries where the ith battery can run a computer for batteries[i] minutes. You are interested in running all n computers simultaneously using the given batteries. Init

maxRunTime.js

/**
 * Calculates the maximum running time for `n` computers
 * given a set of batteries with different capacities.
 *
 * @param {number} n - Number of computers
 * @param {number[]} batteries - Array of battery capacities
 * @return {number} - Maximum possible running time
 */
var maxRunTime = function(n, batteries) {
    // Step 1: Compute the total available power across all batteries
    let totalPower = 0;
    for (let power of batteries) {
        totalPower += power;
    }

    // Step 2: Define binary search boundaries
    // Minimum possible time is 1
    // Maximum possible time is average power per computer (upper bound)
    let left = 1;
    let right = Math.floor(totalPower / n);

    // Step 3: Binary search to find the maximum feasible running time
    while (left < right) {
        // Midpoint (biased upward to avoid infinite loop)
        let mid = right - Math.floor((right - left) / 2);

        // Step 4: Calculate how much power can be used if each computer runs for `mid` time
        let usablePower = 0;
        for (let power of batteries) {
            // Each battery can contribute at most `mid` units of power
            usablePower += Math.min(power, mid);
        }

        // Step 5: Check feasibility
        if (usablePower >= n * mid) {
            // Enough power → try longer time
            left = mid;
        } else {
            // Not enough power → reduce time
            right = mid - 1;
        }
    }

    // Step 6: Return the maximum feasible running time
    return left;
};