Create lexicographically-minimum-string-after-removing-stars.cpp

Author: kamyu104

C++/lexicographically-minimum-string-after-removing-stars.cpp

@@ -0,0 +1,26 @@
+// Time:  O(n + 26)
+// Space: O(n + 26)
+
+// greedy, hash table, stack
+class Solution {
+public:
+    string clearStars(string s) {
+        vector<vector<int>> lookup(26);
+        for (int i = 0; i < size(s); ++i) {
+            if (s[i] != '*') {
+                lookup[s[i] - 'a'].emplace_back(i);
+                continue;
+            }
+            for (auto& stk : lookup) {
+                if (empty(stk)) {
+                    continue;
+                }
+                s[stk.back()] = '*';
+                stk.pop_back();
+                break;
+            }
+        }
+        s.erase(remove(begin(s), end(s), '*'), end(s));
+        return s;
+    }
+};