乐队站位

/**
 * @param {number} num
 * @param {number} xPos
 * @param {number} yPos
 * @return {number}
 */
 var orchestraLayout = function(num, xPos, yPos) {
    let 
        count = 0,
        g = {
            w: num, h: num
        }
    let xT = xPos, xB = num-xPos-1, yL = yPos, yR = num-1-yPos;
    let short = [xT, xB, yL, yR].sort((a,b) => a-b).shift();
    if (short == 1) {
        count += num*4 - 4
    } else if (short != 0) {
        count += ( ((num * 4 - 4) + ((num - 2 * (short-1)) * 4 - 4)) ) * ( short % 9) / 2
        // console.log('count', count)
        count = count % 9
    }
    g.w -= 2 * short
    g.h -= 2 * short
    let curL = short,
        curC = short,
        maxL = num - short - 1,
        maxC = num - short - 1,
        dir = 1; // 1 : first line from left to right, 2: right column from top to bottom, 3: bottom line from right to left, 4: left column from bottom to top
    // console.log('xPos', xPos, 'yPos', yPos, 'num', num)
    // console.log('curL', curL, 'curC', curC, 'short', short)
    // console.log('maxL', maxL, 'maxC', maxC, 'width', g.w)
    while (checkCurLorC()) {
        goNext()
    }
    // console.log('count', count)
    // console.log('curl:', curL, 'curC:', curC, "maxL:", maxL, "maxC:", maxC, "count:", count, count%9, "dir:", dir)
    switch(dir) {
        case 1:
            count += (yPos-curC + 1)
            break;
        case 2:
            count += (xPos - curL + 1)
            break;
        case 3:
            count += (maxC - yPos + 1)
            break;
        case 4:
            count += (maxL - xPos + 1)
            break;
    }
    // console.log('count', count)
    function checkCurLorC() {
        if (curL == xPos && dir == 1) {
            return false
        } else if (curC == yPos && dir == 4) {
            return false
        } else if (maxL == xPos && dir == 3) {
            return false
        } else if (maxC == yPos && dir == 2) {
            return false
        }
        return true
    }
    function goNext() {
        switch (dir) {
            case 1:
                count += g.w;
                g.h--
                curL++;
                dir++
                break;
            case 2:
                count += g.h
                g.w --
                maxC--;
                dir++
                break;
            case 3:
                count += g.w
                g.h --
                maxL--;
                dir++
                break;
            case 4:
                count += g.h
                g.w --
                curC++
                dir=1
                break;
        }
    }
    return count % 9 || 9
};