蓝桥杯冲刺-day02

day2!

AcWing 1208 翻硬币

注意每次都是两个硬币一起反转的，第二个会被强制

import java.io.*;
import java.util.*;

public class Main{
    
    
    
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        char[] s1 = sc.next().toCharArray(); //初始状态
        char[] s2 = sc.next().toCharArray(); //目标状态
        
        int res = 0;
        for(int i=0;i<s1.length-1;i++){
            if(s1[i]!=s2[i]){
                res ++;
                if(s2[i]=='*'){
                    s1[i]='*';
                }else{
                    s1[i]='o';
                }
                
                //一次2个硬币
                if(s1[i+1]=='*'){
                    s1[i+1]='o';
                }else{
                    s1[i+1]='*';
                }
                
            }
        }
        
        System.out.println(res);
    }
}

AcWing 789 数的范围

import java.io.*;
import java.util.*;
public class Main {
	
	
	
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		int m = sc.nextInt();
		int[] q = new int[n]; //q升序
		for(int i=0;i<n;i++) q[i] = sc.nextInt();
		
		while(m-->0){
			int x = sc.nextInt(); 
			
			//1. 找到元素k的起始位置和终止位置（位置从0开始计数）
			int l = 0;
			int r = n-1;
			
			while(l<r){
				int mid = (l + r) >> 1;
				if(q[mid]>=x) r = mid;
				else l = mid+1;
			}
			
			if(q[l]!=x) System.out.println("-1 -1");
			else{
				System.out.print(l + " ");
				l = 0;
				r = n-1;
				while(l<r){
					int mid = (l + r + 1) >> 1;
					if(q[mid]<=x) l = mid;
					else r = mid -1;
				}
				System.out.println(l);
			}
			
		}
		
	}
	
}

AcWing 790 数的三次方根

import java.util.Scanner;

public class Main {
	
	
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		double num = sc.nextDouble();
		
		double l = num > 0 ? 0 : num;
		double r = num > 0 ? num : 0;
		
		while(r - l > 1e-8){
			double mid = (l + r)/2;
			if(mid*mid*mid>=num) r = mid;
			else l = mid;
		}
		
		System.out.println(String.format("%.6f", l));
	}
}