day35打卡

11. 柠檬水找零

var lemonadeChange = function(bills) {
    let five = 0, ten = 0;
    for (const bill of bills) {
        if (bill === 5) {
            five += 1;
        } else if (bill === 10) {
            if (five === 0) {
                return false;
            }
            five -= 1;
            ten += 1;
        } else {
            if (five > 0 && ten > 0) {
                five -= 1;
                ten -= 1;
            } else if (five >= 3) {
                five -= 3;
            } else {
                return false;
            }
        }
    }
    return true;
};

12. 根据身高重建队列

var reconstructQueue = function(people) {
    let queue = []
    people.sort((a, b ) => {
        if(b[0] !== a[0]) {
            return b[0] - a[0]
        } else {
            return a[1] - b[1]
        }
        
    })

    for(let i = 0; i < people.length; i++) {
        queue.splice(people[i][1], 0, people[i])
    }
    return queue
};

13. 用最少数量的箭引爆气球

var findMinArrowShots = function(points) {
    if (!points.length ) {
        return 0;
    }

    points.sort((a, b) => a[1] - b[1]);
    let pos = points[0][1]
    let ans = 1;
    for (let balloon of points) {
        if (balloon[0] > pos) {
            pos = balloon[1];
            ans++;
        }
    }
    return ans;
};