Create minimum-number-of-keypresses.cpp

Author: kamyu104

C++/minimum-number-of-keypresses.cpp

@@ -0,0 +1,19 @@
+// Time:  O(n)
+// Space: O(1)
+
+// greedy, sort
+class Solution {
+public:
+    int minimumKeypresses(string s) {
+        vector<int> cnt(26);
+        for (const auto& c : s) {
+            ++cnt[c - 'a'];
+        }
+        sort(rbegin(cnt), rend(cnt));
+        int result = 0;
+        for (int i = 0; i < size(cnt); ++i) {
+            result += cnt[i] * (i / 9 + 1);
+        }
+        return result;
+    }
+};