diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..5de0996
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,19 @@
+/build*
+docs/build*
+/xml
+docs/xml
+out
+mpich
+cmake-build-*
+.idea/
+.vs/
+.vscode/
+scripts/variants*.csv
+scripts/variants*.xlsx
+*venv*
+sln/
+CMakeSettings.json
+.DS_Store
+.cache
+install
+*.pyc
diff --git a/src/alg.cpp b/src/alg.cpp
index 93f44be..c4ab837 100644
--- a/src/alg.cpp
+++ b/src/alg.cpp
@@ -1,24 +1,71 @@
 // Copyright 2025 UNN-CS
-#include <cstdint>
 #include "alg.h"
 
+#include <cstdint>
+#include <vector>
 
 bool checkPrime(uint64_t value) {
-  // вставьте код функции
+  if (value < 2) {
+    return false;
+  }
+  if (value == 2 || value == 3) {
+    return true;
+  }
+  for (uint64_t i = 2; i * i <= value; i++) {
+    if ((value % i) == 0) {
+      return false;
+    }
+  }
   return true;
 }
 
 uint64_t nPrime(uint64_t n) {
-  // вставьте код функции
-  return 2;
+  if (n == 0) {
+    return 0;
+  }
+
+  uint64_t position = 0;
+  uint64_t desired = 1;
+
+  while (position < n) {
+    desired++;
+    if (checkPrime(desired))
+      position++;
+  }
+  return desired;
 }
 
 uint64_t nextPrime(uint64_t value) {
-  // вставьте код функции
-  return 2;
+  if (value == UINT64_MAX) {
+    return 0;
+  }
+
+  uint64_t next = value + 1;
+  while (!checkPrime(next)) next++;
+  return next;
 }
 
 uint64_t sumPrime(uint64_t hbound) {
-  // вставьте код функции
-  return 2;
-}
+  if (hbound <= 2) {
+    return 0;
+  }
+
+  std::vector<bool> is_prime(hbound, true);
+  is_prime[0] = false;
+  is_prime[1] = false;
+
+  for (uint64_t i = 2; i * i < hbound; i++) {
+    if (is_prime[i]) {
+      for (uint64_t j = i * i; j < hbound; j += i) {
+        is_prime[j] = false;
+      }
+    }
+  }
+  uint64_t sum = 0;
+  for (uint64_t i = 0; i < hbound; i++) {
+    if (is_prime[i]) {
+      sum += i;
+    }
+  }
+  return sum;
+}
\ No newline at end of file
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index e66c6d8..62ce77b 100755
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -3,7 +3,7 @@ include(FetchContent)
 FetchContent_Declare(
   googletest
   GIT_REPOSITORY https://github.com/google/googletest.git
-  GIT_TAG        release-1.11.0
+  GIT_TAG        release-1.12.0
 )
 FetchContent_MakeAvailable(googletest)
 
@@ -28,5 +28,4 @@ target_link_libraries(${PROJECT_NAME}.test
 #target_link_libraries(GTest::GTest INTERFACE gtest_main)  
 #target_link_libraries(${PROJECT_NAME}.test ${PROJECT_NAME})
 # target_compile_definitions(${PROJECT_NAME}.test 
-#   PRIVATE TEST_DIR="${CMAKE_CURRENT_LIST_DIR}/test")
-
+#   PRIVATE TEST_DIR="${CMAKE_CURRENT_LIST_DIR}/test")
\ No newline at end of file
diff --git a/test/tests.cpp b/test/tests.cpp
index 3980306..d3e110a 100644
--- a/test/tests.cpp
+++ b/test/tests.cpp
@@ -4,7 +4,6 @@
 #include <cstdint>
 #include "alg.h"
 
-
 TEST(st1, sumPrime1) {
   uint64_t res = sumPrime(2000000);
   uint64_t expected = 142913828922;
@@ -15,3 +14,72 @@ TEST(st1, sumPrime2) {
   uint64_t expected = 17;
   EXPECT_EQ(expected, res);
 }
+
+TEST(CheckPrimeTest, SmallPrimes) {
+    EXPECT_TRUE(checkPrime(2));
+    EXPECT_TRUE(checkPrime(3));
+    EXPECT_TRUE(checkPrime(5));
+    EXPECT_TRUE(checkPrime(7));
+}
+
+TEST(CheckPrimeTest, SmallNonPrimes) {
+    EXPECT_FALSE(checkPrime(0));
+    EXPECT_FALSE(checkPrime(1));
+}
+
+TEST(CheckPrimeTest, NonPrimes) {
+    EXPECT_FALSE(checkPrime(4));
+    EXPECT_FALSE(checkPrime(9));
+    EXPECT_FALSE(checkPrime(15));
+    EXPECT_FALSE(checkPrime(25));
+}
+
+TEST(CheckPrimeTest, LargePrime) {
+    EXPECT_TRUE(checkPrime(982451653));
+}
+
+TEST(NPrimeTest, ZeroIndex) {
+    EXPECT_EQ(nPrime(0), 0);
+}
+
+TEST(NPrimeTest, FirstPrimes) {
+    EXPECT_EQ(nPrime(1), 2);
+    EXPECT_EQ(nPrime(2), 3);
+    EXPECT_EQ(nPrime(3), 5);
+    EXPECT_EQ(nPrime(4), 7);
+    EXPECT_EQ(nPrime(5), 11);
+}
+
+TEST(NPrimeTest, LargerPrimes) {
+    EXPECT_EQ(nPrime(10), 29);
+    EXPECT_EQ(nPrime(25), 97);
+}
+
+TEST(NextPrimeTest, NextAfterPrimes) {
+    EXPECT_EQ(nextPrime(3), 5);
+    EXPECT_EQ(nextPrime(7), 11);
+    EXPECT_EQ(nextPrime(13), 17);
+}
+
+TEST(NextPrimeTest, NextAfterSmall) {
+    EXPECT_EQ(nextPrime(1), 2);
+    EXPECT_EQ(nextPrime(2), 3);
+    EXPECT_EQ(nextPrime(4), 5);
+    EXPECT_EQ(nextPrime(10), 11);
+}
+
+TEST(NextPrimeTest, MaxValue) {
+    EXPECT_EQ(nextPrime(UINT64_MAX), 0);
+}
+
+TEST(SumPrimeTest, SumBelowSmallBounds) {
+    EXPECT_EQ(sumPrime(2), 0);
+    EXPECT_EQ(sumPrime(3), 2);
+    EXPECT_EQ(sumPrime(6), 10);
+}
+
+TEST(SumPrimeTest, SumBelowLargerBounds) {
+    EXPECT_EQ(sumPrime(11), 17);
+    EXPECT_EQ(sumPrime(12), 28);
+    EXPECT_EQ(sumPrime(20), 77);
+}
\ No newline at end of file