中国大学MOOC-数据结构基础习题集、07-2、Insert or Merge

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
    static String line;
    static int N;
    static int[] test1;
    static int[] test2;
    static int[] check;

    public static void main(String[] args) throws IOException {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        line = in.readLine();
        N = Integer.parseInt(line);
        line = in.readLine();
        String[] string = line.split(" ");
        test1 = new int[N];
        test2 = new int[N];
        check = new int[N];
        for (int i = 0; i < N; i++) {
            test1[i] = Integer.parseInt(string[i]);
        }
        for (int i = 0; i < N; i++) {
            test2[i] = Integer.parseInt(string[i]);
        }
        line = in.readLine();
        string = line.split(" ");
        for (int i = 0; i < N; i++) {
            check[i] = Integer.parseInt(string[i]);
        }
        Merge_sort(test1, N);
        
        Insert_sort(test2, N);
        

    }
    
    public static void ouput(int[] n){
        for (int i = 0; i < N - 1; i++) {
            System.out.print(n[i]);
            System.out.print(" ");
        }
        System.out.print(n[N - 1]);
    }
    static boolean isEqual(int a[], int b[], int n)
    {
        for(int i=0; i<n; i++)
            if(a[i] != b[i])
                return false;
        return true;
    }

    static void Insert_sort(int[] A, int N) {
        boolean flag=false;
        for (int i = 1; i < N; i++) {
            int temp = A[i];
            int j;
            for (j = i; j > 0 && A[j - 1] > temp; j--) {
                A[j] = A[j - 1];
            }
            A[j] = temp;
            if(flag==true){
                System.out.println("Insertion Sort");
                ouput(A);
                break;
            }
            if(isEqual(A,check,N)){
                flag=true;
            }
            if(flag==true&&i==(N-1)){
                System.out.println("Insertion Sort");
                ouput(A);
                break;
            }
        }
    }

    static void Merge_sort(int[] A, int N) {
        boolean flag=false;
        int length = 1;
        int[] TmpA = new int[N];
        while (length < N) {
            Merge_pass(A, TmpA, N, length);
            if(flag==true){
                System.out.println("Merge Sort");
                ouput(A);
                break;
            }
            if(isEqual(A,check,N)){
                flag=true;
            }
            length *= 2;
            Merge_pass(TmpA, A, N, length);
            if(flag==true){
                System.out.println("Merge Sort");
                ouput(A);
                break;
            }
            if(isEqual(A,check,N)){
                flag=true;
            }
            length *= 2;
            if(flag==true&&length>N){
                System.out.println("Merge Sort");
                ouput(A);
                break;
            }
        }
    }

    static void Merge_pass(int[] A, int[] TmpA, int N, int length) {// length当前有序子列的长度
        int i;
        for (i = 0; i <= N - 2 * length; i += 2 * length) {
            Merge(A, TmpA, i, i + length, i + 2 * length - 1);
        }
        if (i + length < N)
            Merge(A, TmpA, i, i + length, N - 1);
        else
            for (int j = i; j < N; j++)
                TmpA[j] = A[j];

    }

    /**
     * 
     * @param A
     * @param L
     *            左边起始位置
     * @param R
     *            右边起始位置
     * @param RightEnd
     *            右边终点位置
     * @return
     */
    static void Merge(int[] A, int[] TmpA, int L, int R, int RightEnd) {
        int LeftEnd = R - 1;// 左边终点位置。假设左右两列挨着
        int Tmp = L;// 存放结果的数组的初始位置
        int NumElements = RightEnd - L + 1;// 元素总数
        while (L <= LeftEnd && R <= RightEnd) {
            if (A[L] < A[R])
                TmpA[Tmp++] = A[L++];
            else
                TmpA[Tmp++] = A[R++];
        }
        while (L <= LeftEnd) {// 直接复制左边剩下的
            TmpA[Tmp++] = A[L++];
        }
        while (R <= RightEnd) {// 直接复制右边剩下的
            TmpA[Tmp++] = A[R++];
        }
        for (int i = 0; i < NumElements; i++, RightEnd--) {
            A[RightEnd] = TmpA[RightEnd];
        }
    }
}