퀵소트 구현

Author: holmir97

QuickSort/HelpSorting.java

@@ -0,0 +1,48 @@
+public class HelpSorting {
+    static int cnt;
+
+    // Sort 배열 결과 출력
+    static void printArrVer1(int[] arr, String sortName) {
+
+        System.out.println(sortName + "[" + arr.length + "]인 배열 정렬 결과.");
+        System.out.println("Count the number of Key comparisons : " + cnt);
+        if (arr.length < 40) {
+            System.out.print("정렬된 값: ");
+            for (int n = 0; n < arr.length; n++)
+                System.out.print(arr[n] + " ");
+            System.out.print("\n");
+        }
+    }
+
+    // Sort 클래스 안에서 count를 독립적으로 계산했을때 사용하는 배열 출력 메소드
+    static void printArrVer2(int[] arr, String sortName,int cnt) {
+
+        System.out.println(sortName + "[" + arr.length + "]인 배열 정렬 결과.");
+        System.out.println("Count the number of Key comparisons : " + cnt);
+        if (arr.length < 40) {
+            System.out.print("정렬된 값: ");
+            for (int n = 0; n < arr.length; n++) {
+                System.out.print(arr[n] + " ");
+            }
+            System.out.print("\n");
+        }
+    }
+
+    // a,b의 값을 비교하여 결과 반환
+    static int Compare(int a, int b) {
+        cnt++;
+        if (a < b)
+            return 1;
+        else if (a == b)
+            return 0;
+        else
+            return -1;
+    }
+
+    //단순 스왑 함수
+    static void swap(int arr[], int a, int b){
+        int temp = arr[a];
+        arr[a] = arr[b];
+        arr[b] = temp;
+    }
+}

QuickSort/QuickSortVer1.java

@@ -0,0 +1,37 @@
+// 마지막 값을 pivot으로 하는 퀵소트
+public class QuickSortVer1 extends HelpSorting {
+
+    static void sort(int[]arr, String sortName){
+        cnt = 0;
+        quickSortLastPivot(arr,0,arr.length-1);
+        //정렬된 배열 출력
+        printArrVer1(arr,sortName);
+    }
+
+    private static void quickSortLastPivot(int[] arr, int left, int right){
+        if(left >= right)
+            return;
+
+        int mid = partitionLast(arr,left,right);
+        quickSortLastPivot(arr,left,mid-1);
+        quickSortLastPivot(arr,mid +1,right);
+    }
+
+    private static int partitionLast(int[] arr, int left, int right){
+        return partition(arr,left,right);
+    }
+
+
+    public static int partition(int[] arr, int left, int right) {
+        int pivot = arr[right];
+        int i = left -1;
+        for(int j=left;j<right;j++) {
+            if(Compare(arr[j],pivot)!=-1) {
+                i++;
+                swap(arr,i,j);
+            }
+        }
+        swap(arr,i+1,right);
+        return i+1;
+    }
+}

QuickSort/QuickSortVer2.java

@@ -0,0 +1,43 @@
+// 랜덤pivot 퀵소트
+public class QuickSortVer2 extends HelpSorting {
+    static void sort(int[]arr, String sortName){
+        cnt = 0;
+
+        quickSortRandomPivot(arr,0,arr.length-1);
+        //정렬된 배열 출력
+        printArrVer1(arr,sortName);
+    }
+
+    private static void quickSortRandomPivot(int[] arr, int left, int right){
+        if(left >= right) {
+            return;
+        }
+
+        int mid = partitionRandom(arr,left,right);
+        quickSortRandomPivot(arr,left,mid-1);
+        quickSortRandomPivot(arr,mid +1,right);
+    }
+
+    //피벗을 랜덤으로 고른 다음 맨마지막 위치로 이동시켜 기존의 파티션 코드 실행
+    public static int partitionRandom(int[] arr, int left, int right) {
+        int index = (int)(Math.random()*(right+1-left)+left);
+        int pivot = arr[index];
+        int i = left -1;
+
+        swap(arr,right,index);
+        return partition(arr,left,right);
+    }
+
+    public static int partition(int[] arr, int left, int right) {
+        int pivot = arr[right];
+        int i = left -1;
+        for(int j=left;j<right;j++) {
+            if(Compare(arr[j],pivot)!=-1) {
+                i++;
+                swap(arr,i,j);
+            }
+        }
+        swap(arr,i+1,right);
+        return i+1;
+    }
+}

QuickSort/QuickSortVer3.java

@@ -0,0 +1,50 @@
+// pivot 은 median of three로 설정
+public class QuickSortVer3 extends HelpSorting {
+    static void sort(int[]arr, String sortName){
+        cnt = 0;
+
+        quickSortMedianOfThreePivot(arr,0,arr.length-1);
+        //정렬된 배열 출력
+        printArrVer1(arr,sortName);
+    }
+
+    private static void quickSortMedianOfThreePivot(int[] arr, int left, int right){
+        if(left >= right)
+            return;
+
+        int mid = partitionMOT(arr,left,right);
+        quickSortMedianOfThreePivot(arr,left,mid-1);
+        quickSortMedianOfThreePivot(arr,mid +1,right);
+    }
+
+
+
+    private static int partitionMOT(int[] arr, int left, int right) {
+        int center = (left+right)/2;
+        if(Compare(arr[left],arr[right])!=-1) {
+            if(Compare(arr[center],arr[right])!=-1)
+                swap(arr,center,right);
+        }
+        else {
+            if(Compare(arr[center],arr[left])!=-1)
+                swap(arr,center,right);
+            else
+                swap(arr,left,right);
+
+        }
+        return partition(arr,left,right);
+    }
+
+    public static int partition(int[] arr, int left, int right) {
+        int pivot = arr[right];
+        int i = left -1;
+        for(int j=left;j<right;j++) {
+            if(Compare(arr[j],pivot)!=-1) {
+                i++;
+                swap(arr,i,j);
+            }
+        }
+        swap(arr,i+1,right);
+        return i+1;
+    }
+}