problems: add can place flowers

Signed-off-by: Matej Focko <mfocko@redhat.com>

problems/can-place-flowers.cpp

@@ -0,0 +1,44 @@
+#include <cassert>
+#include <vector>
+
+using std::vector;
+
+class Solution {
+  public:
+    bool canPlaceFlowers(vector<int> &flowerbed, int n) {
+        int count = 0;
+
+        int left = 0, right;
+        for (vector<int>::size_type i = 0; i < flowerbed.size(); i++) {
+            right = (i + 1 < flowerbed.size()) ? flowerbed[i + 1] : 0;
+
+            if (left == 0 && flowerbed[i] == 0 && right == 0) {
+                count++;
+                left = 1;
+            } else {
+                left = flowerbed[i];
+            }
+        }
+
+        return count >= n;
+    }
+};
+
+int main() {
+    Solution s;
+
+    std::vector flowers{1, 0, 0, 0, 1};
+    assert(s.canPlaceFlowers(flowers, 1));
+    assert(!s.canPlaceFlowers(flowers, 2));
+
+    flowers = {1, 0, 0, 0, 0, 1};
+    assert(!s.canPlaceFlowers(flowers, 2));
+
+    flowers = {1, 0, 0, 0, 1, 0, 0};
+    assert(s.canPlaceFlowers(flowers, 2));
+
+    flowers = {0, 0, 1, 0, 0};
+    assert(s.canPlaceFlowers(flowers, 1));
+
+    return 0;
+}