diff --git a/problem-1/problem-1.test.js b/problem-1/problem-1.test.js
index f54f840..6149459 100644
--- a/problem-1/problem-1.test.js
+++ b/problem-1/problem-1.test.js
@@ -1,4 +1,21 @@
 const bubbleSort = (array) => {
+  const len = array.length;
+
+  for (let i = 0; i < len; i++) {
+    let isChanged = false;
+    for (let j = 0; j < len - i; j++) {
+      if (array[j] > array[j + 1]) {
+        isChanged = true;
+        [array[j], array[j + 1]] = [array[j + 1], array[j]];
+      }
+    }
+
+    if (!isChanged) {
+      return array;
+    }
+  }
+
+  return array;
 };
 
 test.each([
diff --git a/problem-2/problem-2.test.js b/problem-2/problem-2.test.js
index 1e1fe4f..7d17ece 100644
--- a/problem-2/problem-2.test.js
+++ b/problem-2/problem-2.test.js
@@ -1,4 +1,17 @@
 const selectionSort = (array) => {
+  for (let i = 0; i < array.length; i++) {
+    let min = i;
+
+    for (let j = i + 1; j < array.length; j++) {
+      if (array[j] < array[min]) {
+        min = j;
+      }
+    }
+
+    [array[i], array[min]] = [array[min], array[i]];
+  }
+
+  return array;
 };
 
 test.each([
diff --git a/problem-3/problem-3.test.js b/problem-3/problem-3.test.js
index e4450b5..e96ea76 100644
--- a/problem-3/problem-3.test.js
+++ b/problem-3/problem-3.test.js
@@ -1,4 +1,12 @@
 const insertionSort = (array) => {
+  for (let i = 1; i < array.length; i++) {
+    for (let j = i; j > 0; j--) {
+      if (array[j] < array[j - 1]) {
+        [array[j], array[j - 1]] = [array[j - 1], array[j]];
+      }
+    }
+  }
+  return array;
 };
 
 test.each([
diff --git a/problem-4/problem-4.test.js b/problem-4/problem-4.test.js
index 069ccdf..786938b 100644
--- a/problem-4/problem-4.test.js
+++ b/problem-4/problem-4.test.js
@@ -1,4 +1,19 @@
 const shellSort = (array) => {
+  let h = Math.floor(array.length / 2);
+
+  while (h >= 1) {
+    for (let i = h; i < array.length; i++) {
+      for (let j = i; j >= 0; j = j - h) {
+        if (array[j] < array[j - h]) {
+          [array[j], array[j - h]] = [array[j - h], array[j]];
+        }
+      }
+    }
+
+    h = Math.floor(h / 2);
+  }
+
+  return array;
 };
 
 test.each([
diff --git a/problem-5/problem-5.test.js b/problem-5/problem-5.test.js
index 124ce9e..2542ed4 100644
--- a/problem-5/problem-5.test.js
+++ b/problem-5/problem-5.test.js
@@ -1,4 +1,32 @@
-const mergeSort = (array) => {
+const merge = (array, start, mid, end) => {
+  let left = start;
+  let right = mid + 1;
+
+  const temp = [...array];
+
+  for (let i = start; i <= end; i++) {
+    if (left > mid) {
+      array[i] = temp[right++];
+    } else if (right > end) {
+      array[i] = temp[left++];
+    } else if (temp[left] < temp[right]) {
+      array[i] = temp[left++];
+    } else {
+      array[i] = temp[right++];
+    }
+  }
+};
+
+const mergeSort = (array, start = 0, end = array.length - 1) => {
+  if (start >= end) {
+    return;
+  }
+
+  const mid = Math.floor((start + end) / 2);
+
+  mergeSort(array, start, mid);
+  mergeSort(array, mid + 1, end);
+  merge(array, start, mid, end);
 };
 
 test.each([
diff --git a/problem-6/problem-6.test.js b/problem-6/problem-6.test.js
index f335a1f..d1306af 100644
--- a/problem-6/problem-6.test.js
+++ b/problem-6/problem-6.test.js
@@ -1,4 +1,45 @@
-const quickSort = (array) => {
+const partition = (array, start, end) => {
+  let left = start + 1;
+  let right = end;
+
+  const pivot = array[start];
+
+  while (true) {
+    while (array[left] < pivot) {
+      if (left === end) {
+        break;
+      }
+
+      left++;
+    }
+
+    while (pivot < array[right]) {
+      if (right === start) {
+        break;
+      }
+
+      right--;
+    }
+
+    if (left >= right) {
+      break;
+    }
+
+    [array[left], array[right]] = [array[right], array[left]];
+  }
+
+  [array[start], array[right]] = [array[right], array[start]];
+  return right;
+};
+
+const quickSort = (array, start = 0, end = array.length - 1) => {
+  if (start >= end) {
+    return;
+  }
+
+  const j = partition(array, start, end);
+  quickSort(array, start, j - 1);
+  quickSort(array, j + 1, end);
 };
 
 test.each([
diff --git a/problem-7/problem-7.test.js b/problem-7/problem-7.test.js
index 8d36fec..900eacc 100644
--- a/problem-7/problem-7.test.js
+++ b/problem-7/problem-7.test.js
@@ -1,4 +1,32 @@
+const sink = (array, i, len) => {
+  while (2 * i <= len) {
+    let j = 2 * i;
+
+    if (j < len && array[j] < array[j + 1]) {
+      j++;
+    }
+
+    if (!(array[i] < array[j])) {
+      break;
+    }
+
+    [array[i], array[j]] = [array[j], array[i]];
+    i = j;
+  }
+};
+
 const heapSort = (array) => {
+  let len = array.length - 1;
+
+  for (let i = Math.floor(len / 2); i >= 1; i--) {
+    sink(array, i, len);
+  }
+
+  while (len > 1) {
+    [array[1], array[len]] = [array[len], array[1]];
+    len--;
+    sink(array, 1, len);
+  }
 };
 
 test.each([