Lemonade Change LeetCode solution in C++

1
class Solution {
2
 public:
3
  bool lemonadeChange(vector<int> &bills) {
4
    unordered_map<int, int> m;
5

6
    int change = 0;
7
    for (int i = 0; i < bills.size(); i++) {
8
      m[bills[i]]++;
9

10
      if (bills[i] > 5) {
11
        change = bills[i] - 5;
12

13
        if (change == 5) {
14
          if (m[5] > 0) {
15
            m[5]--;
16
          } else {
17
            return false;
18
          }
19
        }
20
        // change = 10
21
        else {
22
          if (m[10] > 0 and m[5] > 0) {
23
            m[10]--;
24
            m[5]--;
25
          } else if (m[5] >= 3) {
26
            m[5] -= 3;
27
          } else {
28
            return false;
29
          }
30
        }
31
      }
32
    }
33

34
    return true;
35
  }
36
};