diff --git a/Dockerfile b/Dockerfile
index 738a8b5..5d9c48f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,10 +1,9 @@
-FROM ubuntu:latest
+FROM alpine:3.19.0
 
-WORKDIR /usr/src/app
+WORKDIR /app
 
-RUN apt-get update; \
-    apt-get install -y --no-install-recommends make g++ libgtest-dev cmake; \
-    rm -rf /var/lib/apt/lists/*
+RUN apk update && \
+    apk add --no-cache build-base cmake gtest-dev
 
 COPY . .
 
diff --git a/src/rainflow.cpp b/src/rainflow.cpp
index 1682322..09e5618 100644
--- a/src/rainflow.cpp
+++ b/src/rainflow.cpp
@@ -111,25 +111,16 @@ RainFlow::Counts RainFlow::count_cycles(const RainFlow::Series& series, double b
                 nmax = n;
 
             auto range = n * binSize;
-            if (counts.find(range) == counts.end()) {
-                counts[range] = cycle.count;
-            } else {
-                counts[range] += cycle.count;
-            }
+            counts[range] += cycle.count;
         }
 
         for (auto n = 1; n < nmax; ++n) {
             auto range = n * binSize;
-            if (counts.find(range) == counts.end())
-                counts[range] = 0.0;
+            counts.emplace(range, 0.0);
         }
     } else {
         for (auto cycle: extract_cycles(series)) {
-            if (counts.find(cycle.range) == counts.end()) {
-                counts[cycle.range] = cycle.count;
-            } else {
-                counts[cycle.range] += cycle.count;
-            }
+            counts[cycle.range] += cycle.count;
         }
     }