Update lemonade-change.cpp

Author: kamyu104

C++/lemonade-change.cpp

@@ -2,6 +2,32 @@
 // Space: O(1)
 
 class Solution {
+public:
+    bool lemonadeChange(vector<int>& bills) {
+        static const vector<int> coins = {20, 10, 5};
+        unordered_map<int, int> counts;
+        for (const auto& bill : bills) {
+            ++counts[bill];
+            auto change = bill - coins.back();
+            for (const auto& coin : coins) {
+                if (change == 0) {
+                        break;
+                }
+                if (change >= coin) {
+                    const auto count = min(counts[coin], change / coin);
+                    counts[coin] -= count;
+                    change -= coin * count;
+                }
+            }
+            if (change != 0) {
+                return false;
+            }
+        }
+        return true;
+    }
+};
+
+class Solution2 {
 public:
     bool lemonadeChange(vector<int>& bills) {
         int five = 0, ten = 0;