蓝桥杯练习第三天

题目2

代码：

package day3;

import java.util.ArrayList;

public class day3_test2 {
    public static int sumOddLengthSubarrays(int[] arr) {
            int result = 0;
            int sum = 0;
            int index = 0;
            int length = arr.length;
            ArrayList<Integer> arrayList =new ArrayList<>();

            while(!(index == length)){
                for(int i=index; i<arr.length; i++){
                    sum += arr[i];
                    arrayList.add(arr[i]);
                    if(arrayList.size() % 2 != 0){
                        result += sum;
                    }
                }
                index += 1;
                arrayList.clear();
                sum = 0;
            }
            return result;
    }

    public static void main(String[] args) {
        int[] arr = {1,4,2,5,3};
        int[] arr1 = {1,2};
        int[] arr2 = {10,12,11};
        System.out.println(sumOddLengthSubarrays(arr));
        System.out.println(sumOddLengthSubarrays(arr1));
        System.out.println(sumOddLengthSubarrays(arr2));
    }
}

运行截图：

题目3

代码：

package day3;

public class day3_test3 {
    public static int numSubarraysWithSum(int[] nums, int goal) {
        int result = 0;
        int count = 0;
        int index = 0;

        while (index != nums.length){
            for(int j=index; j<nums.length; j++){
                result += nums[j];
                if(result == goal){
                    count += 1;
                }
            }
            result = 0;
            index += 1;

        }
        return count;
    }

    public static void main(String[] args) {
        int[] nums = {1,0,1,0,1};
        int[] nums1 = {0,0,0,0,0};
        System.out.println(numSubarraysWithSum(nums,2));
        System.out.println(numSubarraysWithSum(nums1,0));
    }
}

运行截图：

题目4：

代码：

package day3;

public class day3_test4 {
    public static int solute(int k, int r){
//        (((k * num1) -r) % 10 == 0)
            int num1= 1;
            int num2= 1;
           while(true){
               if(k*num2 % 10 == 0){
                  return num2;
               }
               if(((((k * num1) -r) % 10 == 0))){
                   return num1;
               }
               num1++;
               num2++;
           }
    }
    public static void main(String[] args) {
        System.out.println(solute(117,3));
        System.out.println(solute(15,2));
        System.out.println(solute(237,7));
        System.out.println(solute(5,3));
    }
}

运行截图：