Cattle customer network & collar button Network Day 1 summary exercises

First, select the map 

1. 

           

Resolution: 

 

2.

Resolution:

Answer: 14 (interference terms: 1001312)

fun1 (xyz) pass by reference, the value itself is changed.

fun2 (abc) passed by value, parameter change is no effect argument.

abc xyz is assigned, the value 14

3.

Resolution:

A option, occurs when the nested loops, the number of layers is not specified; C options, when nested loops, does not require to be retracted when the writing of code; D option, the expression in parentheses for statement can be omitted . So B option right 

4.

5.

Resolution:

According to the meaning of problems between the two groups is already sorted, just sort of elements within the group can be.

The set of k elements of Comparative sort, the lower bound of the time O (klog2k), a total of n / k groups, i.e. O (klog2k * n / k) = O (nlog2k).

6.

 7.

8.

Parsing: B items were reversed 

 9.

10.

11.

Second, the programming problem

import java.util.Arrays;
class Solution1313 {
    public static void main(String[] args){
        int[] nums={1,2,3,4};
        int[] res=decompressRLElist(nums);
        System.out.println(Arrays.toString(res));
    }
    public static int[] decompressRLElist(int[] nums) {
        int len=0;
        //遍历偶数角标 累加得到新数组的长度
        for(int i=0;i<nums.length;i+=2){
            len+=nums[i];
        }
        int[] res=new int[len];
        //遍历奇数角标 获取需要被多次写入的数据
        //1 2 3 4 
        //2 4 4 4 
        int index=0;
        for(int i=1;i<=nums.length;i+=2){
            for(int j=0;j<nums[i-1];j++){
                res[index++]=nums[i];
            }
        }
        return res;
    }
}

 

class Solution {
    public int findNumbers(int[] nums) {
        int c=0;
        for(int i=0;i<nums.length;i++){
            if((nums[i]>=10&&nums[i]<=100)||(nums[i]>=1000&&nums[i]<=10000)){
                c++;
            }
        }
        return c;

    }
}

 

class Solution {
    public int[] sortArrayByParity(int[] A) {
        int[] B = new int[A.length];
        int left = 0;
        int right=B.length-1;
        for(int i=0;i<A.length;i++){
            if(A[i]%2==0){
                B[left++]=A[i];
            }else{
                B[right--]=A[i];
            
            }
        }
        return B;

    }
}

 

class Solution {
    public int majorityElement(int[] nums) {
        Arrays.sort(nums);
        int m = 0;
        int mcount=0;
        for(int i=0;i<nums.length;){
            if(i>nums.length/2){
                break;
            }
            int count=1;
            for(int j=i+1;j<nums.length;j++){
                if(nums[j]==nums[i]){
                    count++;
                }else{
                    break;
                }
            }
            if(count>mcount){
                mcount=count;
                m=nums[i];
            }
            i+=count;
        }
        return m;

    }
}

 

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Origin blog.csdn.net/q1220668269/article/details/104459061