递归merge排序
package sort; import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.Scanner; public class MergeSort { public static void merge(int[] arr, int[] tmp, int l_start, int r_start, int r_end) { int tmp_pos = l_start; int l_end = r_start-1; int i=l_start; int j = r_start; while(i<=l_end&&j<=r_end){ if(arr[i]<arr[j]){ tmp[tmp_pos++]=arr[i++]; } else{ tmp[tmp_pos++]=arr[j++]; } } while(i<=l_end){ tmp[tmp_pos++]=arr[i++]; } while(j<=r_end){ tmp[tmp_pos++]=arr[j++]; } int N = r_end - l_start+1; for(int k=0;k<N;k++,r_end--){ arr[r_end] = tmp[r_end]; } } public static void mssort(int[] arr, int[] tmp, int left, int right) { if (left < right) { int center = (left + right) / 2; mssort(arr, tmp, left, center); mssort(arr, tmp, center + 1, right); merge(arr, tmp, left, center + 1, right); } } public static void main(String[] args) { int N; Scanner scanner = new Scanner(new BufferedReader(new InputStreamReader( System.in))); N = scanner.nextInt(); int[] arr = new int[N]; int[] tmp = new int[N]; for (int i = 0; i < N; i++) { arr[i] = scanner.nextInt(); } scanner.close(); mssort(arr,tmp,0,arr.length-1); for(int i=0;i<tmp.length;i++){ System.out.println(tmp[i]); } } }