A计划---POJ1804 Brainman

Posted 2022-12-09 光光-Leo

还是一道逆序数的题，再熟悉一下归并排序

import java.util.Scanner;

public class Main 

	static int data[] = null;
	static long step;
	public static void sort(int left,int right,int temp[])
		if(left<right)
			int mid = (left+right)/2;
		    sort(left,mid,temp);
		    sort(mid+1,right,temp);
		    merge(left,mid,right,temp);
		
	
	public static void merge(int left,int mid,int right,int temp[])
		int i = left;
		int j = mid+1;
		int t = 0;
		while(i<=mid&&j<=right)
			if(data[i]<=data[j])
				temp[t++] = data[i++];
			else
				temp[t++] = data[j++];
				step+=mid-i+1;
			
		
		while(i<=mid)
			temp[t++] = data[i++];
		
		while(j<=right)
			temp[t++] = data[j++];
		
		t = 0;
		while(left<=right)
			data[left++] = temp[t++];
		
	
	public static void main(String[] args) 
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int i = 0;
		while(i<n)
			int num = sc.nextInt();
			data = new int[num];
			int j = 0;
			while(j<num)
				data[j++] = sc.nextInt();
			
			int temp[] =new int[num];
			step = 0L;
			Main.sort(0, num-1, temp);
			System.out.println("Scenario #"+(++i)+":");
			System.out.println(step);
			System.out.println("");