diff --git a/histogram.cpp b/histogram.cpp
index 5d85960..641db08 100644
--- a/histogram.cpp
+++ b/histogram.cpp
@@ -3,8 +3,14 @@
 using namespace std;
 
 void find_minmax(const vector<double>& numbers, double& min, double& max) {
+    if (numbers.empty())
+    {
+        min = 0;
+        max = 0;
+        return;
+    }
     max = numbers[0];
-    min = numbers[1];
+    min = numbers[0];
     for (double x : numbers) {
         if (x < min) min = x;
         else if (x > max) max = x;
diff --git a/unittest.cpp b/unittest.cpp
index a9ba7e5..bf37c5e 100644
--- a/unittest.cpp
+++ b/unittest.cpp
@@ -10,3 +10,35 @@ TEST_CASE("distinct positive numbers") {
     CHECK(min == 1);
     CHECK(max == 2);
 }
+
+
+TEST_CASE("distinct negative numbers"){
+    double min = 0;
+    double max = 0;
+    find_minmax({-1, -2}, min, max);
+    CHECK(min == -2);
+    CHECK(max == -1);
+}
+TEST_CASE("vector of the same elements"){
+    double min = 0;
+    double max = 0;
+    find_minmax({3,3,3}, min, max);
+    CHECK(min == 3);
+    CHECK(max == 3);
+}
+
+TEST_CASE("single element vector") {
+    double min = 0;
+    double max = 0;
+    find_minmax({7}, min, max);
+    CHECK(min == 7);
+    CHECK(max == 7);
+}
+
+TEST_CASE("empty vector") {
+    double min = 0;
+    double max = 0;
+    find_minmax({}, min, max);
+    CHECK(min == 0);
+    CHECK(max == 0);
+}