23届秋招阿里笔试算法题

柔光的暖阳◎ 2024-04-06 10:26 28阅读 0赞

import java.util.Scanner;
    
    //23届秋招阿里笔试第一题：二进制求解(100%)
    public class Main1 {
    
    	public static void f1(int n) {
    		String str= Integer.toString(n, 2);
    		for (int i = 0; i < str.length(); i++) {
    			if(str.charAt(i)=='1') {
    				System.out.print((char)('a'+str.length()-1-i));
    			}
    		}
    	}
    	
    	public static void main(String[] args) {
    		Scanner sc=new Scanner(System.in);
    		f1(sc.nextInt());
    	}
    
    }

import java.util.Scanner;
    
    //23届秋招阿里笔试第二题：树技巧求解(0%)
    public class Main2 {
    
    	public static void f2(int[] arr,int[][] help) {
    		int sum=0;
    		for (int i = 0; i < arr.length; i++) {
    			for (int j = 0; j < help.length; j++) {
    				if(help[1][j]==i+1) {
    					sum+=(i+1-help[0][j]);
    				}
    			}
    		}
    		System.out.println(sum);
    	}
    	
    	public static void main(String[] args) {
    		Scanner sc=new Scanner(System.in);
    		int n=sc.nextInt();
    		int[] arr=new int[n];
    		int[][] help=new int[2][n-1];
            for (int i = 0; i < n-1; i++) {
            	help[0][i]=sc.nextInt();
                help[1][i]=sc.nextInt();
    		}
            f2(arr, help);
    	}
    
    }

import java.util.Scanner;
    
    //23届秋招阿里笔试第三题：动规求解(20%)
    public class Main3 {
    
    	public static void f3(String str) {
    		Long[] arr=new Long[str.length()];
    		arr[0]=1L;
    		for (int i = 1; i < arr.length; i++) {
    			arr[i]=1+arr[i-1];
    			for (int j = i-1; j >=0; j--) {
    				if(check(str.substring(j, i+1))) {
    					arr[i]++;
    				}
    			}
    		}
    		System.out.println(arr[str.length()-1]);
    	}
    	
    	public static boolean check(String str) {
    		int[] help=new int[26];
    		for (int i = 0; i < str.length(); i++) {
    			help[str.charAt(i)-'a']++;
    		}
    		boolean flag=false;
    		for (int i = 0; i < help.length; i++) {
    			if(help[i]%2!=0) {
    				if(flag) {
    					return false;
    				}
    				flag=true;
    			}
    		}
    		return flag;
    	}
    	
    	public static void main(String[] args) {
    		Scanner sc=new Scanner(System.in);
    		f3(sc.next());
    	}
    
    }