Create number-of-laser-beams-in-a-bank.cpp

Author: kamyu104

C++/number-of-laser-beams-in-a-bank.cpp

@@ -0,0 +1,18 @@
+// Time:  O(m * n)
+// Space: O(1)
+
+class Solution {
+public:
+    int numberOfBeams(vector<string>& bank) {
+        int result = 0, prev = 0;
+        for (const auto& x : bank) {
+            const auto& cnt = count(cbegin(x), cend(x), '1');
+            if (!cnt) {
+                continue;
+            }
+            result += prev * cnt;
+            prev = cnt;
+        }
+        return result;
+    }
+};