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本文主要是【java】——算法刷题常用方法的文章，如果有什么需要改进的地方还请大佬指出⛺️
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目录
- 📑前言
- 1.最大公约数gcd
- 2.唯一分解定理
- 3.欧拉筛
- 4.单调队列实现滑动窗口
- 5.数组前缀和
- 📑文章末尾
1.最大公约数gcd
package 蓝桥杯练习;import java.util.Scanner;public class 最大公约数 {public static void main(String[] args) {// TODO Auto-generated method stubScanner sc = new Scanner(System.in);int a = sc.nextInt();int b = sc.nextInt();System.out.println(gcd(a, b));System.out.println(a*b/gcd(a, b));}public static int gcd(int a,int b) {return b==0?a:gcd(b, a%b);}}2.唯一分解定理
package 蓝桥杯练习;import java.util.Scanner;public class 唯一分解定理 {public static void main(String[] args) {// TODO Auto-generated method stubScanner sc = new Scanner(System.in);while(sc.hasNext()) {int n = sc.nextInt();System.out.println(syz(n));}}public static int syz(int n) {int cnt = 1;int bak = n;for(int i=2;i*i<=n;i++) {int num = 0;while(bak%i==0) {num++;bak/=i;}cnt = cnt*(num+1);}if (bak > 1) {cnt++;}return cnt;}}3.欧拉筛
package 蓝桥杯练习;public class 欧拉筛 {public static void main(String[] args) {// TODO Auto-generated method stubint N = 1000;int prime[] = new int[N];boolean isp[] = new boolean[N+5];int count = 0;for(int i=2;i<=N;i++) {if(isp[i]==false) prime[count++]=i;for(int j=0;j<count&&prime[j]*i<=N;j++) {isp[i*prime[j]]=true;//素数的i倍一定是合数if(i%prime[j]==0) break;}}for(int i=0;i<count;i++) {System.out.println(prime[i]);}System.out.println("共有"+count+"个素数");}}4.单调队列实现滑动窗口
package 蓝桥杯练习;import java.util.ArrayDeque;
import java.util.Deque;
import java.util.Scanner;public class 单调队列实现滑动窗口1 {/*
8 3
1 3 4 7 6 2 5 1*/public static void main(String[] args) {// TODO Auto-generated method stub/** 长度为n的数组 长度为m的窗口，求数组中每个长度为m的窗口中的最大值* * n=8 m = 3* 1 3 4 7 6 2 5 1*/Scanner sc = new Scanner(System.in);int n = sc.nextInt();int m = sc.nextInt();int a[] = new int[n];for(int i=0;i<n;i++) {a[i] = sc.nextInt();}Deque<Integer> q = new ArrayDeque<>();for(int i=0;i<n;i++) {//保证队头元素一定是在窗口的 i-3+1while(!q.isEmpty()&&q.peekFirst()<i-m+1) q.pollFirst();while(!q.isEmpty()&&a[q.peekLast()]<a[i]) q.pollLast();q.addLast(i);if (i>=m-1) {System.out.println(a[q.peekFirst()]);}}}}5.数组前缀和
package 蓝桥杯练习;import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;public class 数组前缀和 {
/*
5
1 2 3 4 5*/public static void main(String[] args) throws IOException {// TODO Auto-generated method stubStreamTokenizer sc = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));sc.nextToken();int n = (int)sc.nval;int a[] = new int[n+1];long sum[] = new long[n+1];for(int i=1;i<=n;i++) {sc.nextToken();a[i] = (int)sc.nval;}for(int i=1;i<=n;i++) {sum[i]=a[i]+sum[i-1];}for(int i=1;i<=n;i++) {System.out.println(sum[i]);}}}📑文章末尾
)
)
)
