Create push-dominoes.cpp

Author: kamyu104

C++/push-dominoes.cpp

@@ -0,0 +1,38 @@
+// Time:  O(n)
+// Space: O(n)
+
+class Solution {
+public:
+    string pushDominoes(string dominoes) {
+        vector<int> force(dominoes.length());
+
+        int f = 0;
+        for (int i = 0; i < dominoes.length(); ++i) {
+            if (dominoes[i] == 'R') {
+                f = dominoes.length();
+            } else if (dominoes[i] == 'L') {
+                f = 0;
+            } else {
+                f = max(f - 1, 0);
+            }
+            force[i] += f;
+        }
+
+        f = 0;
+        for (int i = dominoes.length() - 1; i >= 0; --i) {
+            if (dominoes[i] == 'L') {
+                f = dominoes.length();
+            } else if (dominoes[i] == 'R') {
+                f = 0;
+            } else {
+                f = max(f - 1, 0);
+            }
+            force[i] -= f;
+        }
+        string result;
+        for (const auto& f : force) {
+            result.push_back((f == 0) ? '.' : ((f > 0) ? 'R' : 'L'));
+        }
+        return result;
+    }
+};