蓝桥杯国赛备赛复习——基础算法

一、排序

1.1 快速排序

package 排序;

import java.util.Scanner;

public class 快速排序 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scan = new Scanner(System.in);
		int []a = new int[110];
		int n = scan.nextInt();
		for(int i=0;i<n;i++)
			a[i] = scan.nextInt();
		Q_sort(a,0,n-1);
		for(int i=0;i<n;i++)
			System.out.print(a[i]+" ");
	}
	static void Q_sort(int a[],int l,int r) {
		if(l>=r) return;
		int x = a[l];
		int i = l - 1;
		int j = r + 1;
		while(i<j) {
			do i++; while(a[i]<x);
			do j--; while(a[j]>x);
			if(i<j) {
				int t = a[i];
				a[i] = a[j];
				a[j] = t;
			}
		}
		Q_sort(a,l,j);
		Q_sort(a,j+1,r);
	}
}

1.2 归并排序

package 排序;
import java.util.*;
public class 归并排序 {
	static int []tmp = new int[110];	//辅助数组
	pu