2018华为校招软件，c++做了两道不知道对不对

字符替换

#include<iostream>
#include<string>
#include<math.h>
#include<vector>
using namespace std;
int main()
{
 vector vsit;
 char ch1 = '9', ch2 = '8';
 string str = "9897899";
 string str1 = str;
 cout << str;
 int num = 0;
 num = count(str1.begin(), str1.end(), ch1);
 size_t strIter = str1.size();
 while(strIter) {        
     strIter = str1.rfind(ch1,strIter-1);
     vsit.push_back(strIter);
 }
 //vector中存放目标的位置    
 for (int i = 1; i <pow(2,num); i++) {
     int n = 0, count = 0, j = i;
     str1 = str;
     while (j) {
         j = j >> 1;
         count++;
     }//统计出二进制的位数
     while (count >= n+1) {
         if (i & int(pow(2, n++))) {        
             str1[vsit[n - 1]] = ch2;                
         }                
     }
     cout << "," << str1;        
 }
 system("pause");
}

#include<iostream>
#include<string>
#include<vector>
#include<cctype>
#include<algorithm>
#include<map>
using namespace std;
{
vector<int> vs;
string str = "5 2 4 5 56 56 8 9 2 3 4 5 6 3 45 5 56 9 0 9 9 0 9 0 9 0 8 2123 2123 223 223 2123 223 2123 8 9 8";
string str1;
int num = 0;
map<int, int> numMap;
for (auto i : str) {
    if (isdigit(i))
        str1 += i;
    else {
        num = stoi(str1);
        vs.push_back(num);
        str1 = "";
    }
}    
num = stoi(str1);
vs.push_back(num);
sort(vs.begin(), vs.end());
for (auto j : vs) {        
    numMap[j] += 1;
}
auto map_it = numMap.cbegin();
string ch1, ch2;
int n = 0;
while (map_it != numMap.cend()) {
    ch1 = to_string(map_it->first);
    ch2 = to_string(map_it->second);
    if(!n)
        cout << ch1 << " " << ch2 << " ";
    else
        cout << " " << ch1 << " " << ch2 << " ";
    ++map_it;
    n++;
}
system("pause");
}