3주차 과제

problem-1/problem-1.test.js

@@ -1,4 +1,21 @@
 const bubbleSort = (array) => {
+  for(let i = 0; i <= array.length; i++){
+    let swapped = false;
+
+    for(let j = 0; j < array.length - i; j ++){
+      if(array[j] > array[j + 1]){
+        const temp = array[j];
+
+        array[j] = array[j + 1];
+        array[j + 1] = temp;
+        swapped = true;
+      }
+    }
+
+    if(!swapped) break;
+  }
+
+  return array;
 };
 
 test.each([

problem-2/problem-2.test.js

@@ -1,5 +1,30 @@
+const exchange = (array, i, j) => {
+  [array[i], array[j]] = [array[j], array[i]];
+}
+
+const findMinIndex = (array, startIndex) => {
+  let minIndex = startIndex;
+
+  for(let i = startIndex; i < array.length; i++){
+    if(array[minIndex] > array[i]){
+      minIndex = i;
+    }
+  }
+
+  return minIndex;
+}
+
 const selectionSort = (array) => {
-};
+  for(let i = 0; i <= array.length; i++){
+    const minIndex = findMinIndex(array, i);
+
+    if(minIndex === i ){
+      continue;
+    }
+
+    exchange(array, i , minIndex);
+  }
+}
 
 test.each([
   [[5, 4, 3, 2, 1]],

problem-3/problem-3.test.js

@@ -1,4 +1,15 @@
+const exchange = (array, a, b) => {
+  [array[b], array[a]] = [array[a], array[b]];
+}
+
 const insertionSort = (array) => {
+  for(let i = 1; i < array.length; i++) {
+    let j = i;
+    while(j > 0 && array[j - 1] > array[j]) {
+      exchange(array, j, j - 1);
+      j--;
+    }
+  }
 };
 
 test.each([

problem-4/problem-4.test.js

@@ -1,4 +1,27 @@
+const exchange = (array, j, i) => {
+  [array[j], array[i]] = [array[i], array[j]];
+}
+
 const shellSort = (array) => {
+  let gap = Math.floor(array.length / 2);
+
+  while(gap > 0){
+    for(let i = gap; i < array.length; i++){
+      for(let j = i; j >= 0; j = j - gap){
+
+        if(array[j] < array[j - gap]){
+          exchange(array, j, j - gap);
+        }else {
+          break;
+        }
+
+      }
+    }
+
+    gap = Math.floor(gap / 2);
+  }
+
+
 };
 
 test.each([

problem-5/problem-5.test.js

@@ -1,4 +1,34 @@
-const mergeSort = (array) => {
+const merge = (array, start, mid, end) => {
+  let left = start,
+      right = mid + 1;
+
+  const copyArray = [...array];
+
+  for(let i = start; i <= end; i++){
+    if(left > mid){ // 오른쪽 요소로 이동
+      array[i] = copyArray[right];
+      right++;
+    }else if(right > end){ // 왼쪽 요소로 이동
+      array[i] = copyArray[left];
+      left++;
+    }else if(copyArray[left] < copyArray[right]){ // 왼쪽과 오른쪽 요소 중 왼쪽 값이 더 작을 경우
+      array[i] = copyArray[left];
+      left++;
+    }else{
+      array[i] = copyArray[right]; // 왼쪽과 오른쪽 요소 중 오른쪽 값이 더 작을 경우..
+      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); // 분할한 배열 왼쪽 리스트 정렬
+  mergeSort(array, mid + 1, end); // 분할한 배열 오른쪽 리스트 정렬
+  merge(array, start, mid, end);
 };
 
 test.each([

problem-6/problem-6.test.js

@@ -1,4 +1,60 @@
+
+const shuffle = (array) => {
+  let randomIndex;
+
+  for (let i = array.length; i > 0; i--) {
+    randomIndex = Math.floor(Math.random() * i);
+    i--;
+
+    [array[i], array[randomIndex]] = [array[randomIndex], array[i]];
+  }
+};
+
+
+const exchange = (array, low, high) => {
+  [array[high], array[low]] = [array[low], array[high]];
+}
+
+const less = (a, b) => a < b;
+
+const patition = (array, low, high) => {
+  let left  = low + 1,
+      right = high;
+
+  const pivot = array[low];
+
+  while(true){
+    while(less(array[left], pivot)){
+      if(left === high) break;
+
+      left++;
+    }
+
+    while(less(pivot, array[right])){
+      if(right === low) break;
+
+      right--;
+    }
+
+    if(left >= right) break; // 가리키는 요소가 겹칠 때
+    exchange(array, left, right);
+  }
+
+  exchange(array, low, right);
+  return right;
+}
+
+const sort = (array, low, high) => {
+  if(low >= high) return;
+
+  const index = patition(array, low, high);
+  sort(array, low, index - 1);
+  sort(array, index + 1, high);
+}
+
 const quickSort = (array) => {
+  shuffle(array); // 배열 무작위로 섞음
+  sort(array, 0, array.length - 1);
 };
 
 test.each([

problem-7/problem-7.test.js

@@ -1,4 +1,34 @@
+const exchange = (array, a, b) => {
+  [array[a], array[b]] = [array[b], array[a]];
+}
+
+const less = (a, b) => a < b;
+
+const sink = (array, i, N) => {
+  while(2 * i <= N){
+    let j = 2 * i;
+    if(j < N && less(array[j], array[j + 1])){
+      j++;
+    }
+
+    if(!less(array[i], array[j])) break;
+
+    exchange(array, i, j);
+    i = j;
+  }
+}
 const heapSort = (array) => {
+  let N = array.length - 1;
+
+  for(let i = Math.floor(N / 2); i >= 1; i--){
+    sink(array, i, N);
+  }
+
+  while(N > 1){
+    exchange(array, 1, N);
+    N--;
+    sink(array, 1, N);
+  }
 };
 
 test.each([