cs: add “746. Min Cost Climbing Stairs”

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

cs/min-cost-climbing-stairs.cs

@@ -0,0 +1,17 @@
+public class Solution {
+    public int MinCostClimbingStairs(int[] cost) {
+        int Get(int k) {
+            if (k < 0 || k >= cost.Length) {
+                return 0;
+            }
+
+            return cost[k];
+        }
+
+        for (var i = cost.Length - 1; i >= 0; --i) {
+            cost[i] += Math.Min(Get(i + 1), Get(i + 2));
+        }
+
+        return Math.Min(cost[0], cost[1]);
+    }
+}