Sorting – MaxProductOfThree解題紀錄

function solution(A) {
    // Implement your solution here
    var max_positive = new triplet(true)
    var min_positive = new triplet(false)
    var positive_count = 0
    var max_negative = new triplet(true)
    var min_negative = new triplet(false)
    var negative_count = 0
    var has_zero = false
    for (var i = 0; i < A.length; i++) {
        if (A[i] == 0) has_zero = true
        else if (A[i] > 0) {
            max_positive.compareMax(A[i])
            min_positive.compareMin(A[i])
            positive_count++
        } else {
            max_negative.compareMax(A[i])
            min_negative.compareMin(A[i])
            negative_count++
        }
    }
    if (positive_count >= 3 || (negative_count >= 2 && positive_count > 0)) {
        var pos_3 = 0
        var pos_2_neg_1 = 0
        if (positive_count >= 3) {
            pos_3 = max_positive.max * max_positive.middle * max_positive.min
        }
        if (negative_count >= 2 && positive_count > 0) {
            pos_2_neg_1 = min_negative.middle * min_negative.min * max_positive.max
        }
        return Math.max(pos_3, pos_2_neg_1)
    } else if (has_zero) {
        return 0
    } else {
        //確認該使用2個正數*1個負數還是3個負數
        var max_2_pos_1_neg = -Infinity
        var max_3_neg = -Infinity
        if (negative_count > 0 && positive_count >= 2) {
            max_2_pos_1_neg = min_positive.min * min_positive.middle * max_negative.max
        }
        if (negative_count >= 3) {
            max_3_neg = max_negative.max * max_negative.middle * max_negative.min
        }
        return Math.max(max_2_pos_1_neg, max_3_neg)
    }
}
class triplet {
    constructor(isMaxCompare) {
        var data = isMaxCompare ? -Infinity : Infinity
        this.max = data;
        this.middle = data;
        this.min = data;
    }
    getValue() {
        console.log(this.max, this.middle, this.min)
    }
    compareMax(value) {
        if (value > this.max) {
            this.min = this.middle
            this.middle = this.max
            this.max = value
        } else if (value > this.middle) {
            this.min = this.middle
            this.middle = value
        } else if (value > this.min) {
            this.min = value
        }
    }
    compareMin(value) {
        if (value < this.min) {
            this.max = this.middle
            this.middle = this.min
            this.min = value
        } else if (value < this.middle) {
            this.max = this.middle
            this.middle = value
        } else if (value < this.max) {
            this.max = value
        }
    }
}