class Solution {
    /*  k只粉笔   i从0开始
        每到i需要消耗chalk[i], k -= chalk[i]
        如果k < chalk[i],返回i
    */
    public int chalkReplacer(int[] chalk, int k) {
        int n = chalk.length;
        int num = 0;
        while(k>=chalk[num]){
            k -= chalk[num++];
            if(num==n)
            num = 0;
        }
        return num;
    }
}