The maximum quantity leetcode6133. Grouping (medium)

Thinking: Skills
Find the largest m that satisfies m * (1 + m) / 2 <= n.

class Solution {public:int maximumGroups(vector<int>& grades) {int n = grades.size();int i = 0;for (; i * (i + 1) <= 2 * n; ++i) {}return i - 1;}};