每日打卡-LeetCode-1894-找到需要补充粉笔的学生编号

class Solution {
 public:
  int chalkReplacer(vector<int>& chalk, int k) {
    int n = chalk.size();
    vector<long> s(n + 1, 0);
    for (int i = 1; i <= n; i++) {
      s[i] = s[i - 1] + chalk[i - 1];
    }
    int cnt = 0;
    int m = (int)(k % s[n]);
    int l = 0, r = n - 1;
    while (l < r) {
      int mid = l + r >> 1;
      if (s[mid] >= m) {
        r = mid;
      } else {
        l = mid + 1;
      }
    }
    return s[l] <= m ? l : l - 1;
  }
};