mergSortArr

#include <iostream>
#include <vector>
#include <string>
using namespace  std;

void mergeSortNum(vector<int>& vec1, int m, vector<int>& vec2, int n)
{
    int position = m-- + n-- -1;

    while(m >= 0 and n>= 0)
    {
        vec1[position--] = vec1[m] > vec2[n] ? vec1[m--] : vec2[n--];
    }

    while(n >= 0)
    {
        vec1[position--] = vec2[n--];
    }
}

    int singleNumber(vector<int>& A) 
    {
        // write code here
        auto size = A.size();
        int singleNum = 0;
        for(decltype(size) i = 0; i < size; i++)
        {
            singleNum ^= A[i];
        }
        return singleNum;
    }


int main()
{
    // vector<int> vec1 = {1,2,3,0,0,0};
    // vector<int> vec2 = {2,5,6};
    // int m = 3;
    // int n = 3;
    // mergeSortNum(vec1 , m, vec2, n);
    // for(auto& vec : vec1)
    // {
    //     cout << vec <<endl;
    // }

    // vector<int> vec3 = {2,2,3};

    // cout << singleNumber(vec3) <<endl;

    int i, f = 0;
    double x = 1, y1 = 2.1 / 1.9, y2 = 1.9 / 2.1;
    for ( i = 1; i < 22; i++ )
    {
        x = x * y1;
    }
    while ( x != 1.0 )
    {
        x = x * y2; f++;
    }
    printf( "%d \n", f );//doubel f 21,float f 无线循环
    getchar();
    return 0;
}