475-Heater

var findRadius = function(houses, heaters) {
    var max = 0    for(let i = 0 ; i < houses.length ; i ++) {
        var house_position = houses[i]
        var r = Infinity        for(let j = 0 ; j < heaters.length ; j ++) {
            var heat_position = heaters[j]
            var reduce = Math.abs(house_position - heat_position)
            r = Math.min(r,reduce)
        }
        max = Math.max(r,max)
    }
    return max
};

var findRadius = function(houses, heaters) {
    var r = 0    for(let i = 0 ; i < houses.length ; i ++) {
        var house_position = houses[i]
        let left = 0 , right = heaters.length - 1        // Find the heat_position closest to house_position // That is, find the rightmost insertion point of house_position while(left <= right && right < heaters.length) {
            let mid = left + Math.floor((right - left) / 2)
            var heat_position = heaters[mid]
            // If the one found is not greater than, go to the right if(heat_position <= house_position) {
                left = mid + 1            } else {
                right = mid - 1            }
        }
        // The insertion point found at this time is not necessarily the closest one. The one on the left is smaller than it, so we need to compare it var R = Math.abs(heaters[right] - house_position)
        if(right > 0) {
            R = Math.min( Math.abs( heaters[right - 1] - house_position) , R)
        }
        r = Math.max(r,R)
    }
    return r
};