JavaScript O((m + n) log n) using binary search


  • 0
    var findRadius = function(houses, heaters) {
        heaters.sort((a, b) => a - b);
        return houses.reduce((max, house) => Math.max(max, closestHeaterDistance(house, heaters, 0, heaters.length - 1)), 0);
    };
    
    function closestHeaterDistance(house, heaters, low, high) {
        if (low === high) return Math.abs(house - heaters[low]);
        let mid = Math.floor((low + high) / 2);
        if (house < heaters[mid]) {
            if (mid === 0) return Math.abs(house - heaters[0]);
            if (house > heaters[mid - 1]) {
                return Math.min(Math.abs(house - heaters[mid]), Math.abs(house - heaters[mid - 1]));
            }
            return closestHeaterDistance(house, heaters, low, mid - 1);
        } else if (house > heaters[mid]) {
            if (mid === heaters.length - 1) return Math.abs(house - heaters[heaters.length - 1]);
            if (house < heaters[mid + 1]) {
                return Math.min(Math.abs(house - heaters[mid]), Math.abs(house - heaters[mid + 1]));
            }
            return closestHeaterDistance(house, heaters, mid + 1, high)
        }
        return 0;
    }
    

    The strategy is to maximize the minimum distance, finding the minimum by binary search.


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