fix: harden electronics shop io parsing

code/online_challenges/src/hackerrank/Electronics_Shop/Electronics_Shop.cpp

@@ -8,62 +8,128 @@ vector<string> split_string(string);
 /*
  * Complete the getMoneySpent function below.
  */
-int getMoneySpent(vector<int> keyboards, vector<int> drives, int b) {
-    int i,sum=0,j,k=0,ans=-1;
-    sort(keyboards.begin(),keyboards.end());
-    sort(drives.begin(),drives.end());
-    for(i=0;i<keyboards.size();i++)
-    {
-    for(j=0;j<drives.size();j++)
+int getMoneySpent(vector<int> keyboards, vector<int> drives, int b)
+{
+    int i, sum = 0, j, k = 0, ans = -1;
+    sort(keyboards.begin(), keyboards.end());
+    sort(drives.begin(), drives.end());
+    for (i = 0; i < keyboards.size(); i++)
     {
-      sum=keyboards[i]+drives[j];
-      if(sum<=b&&sum>ans)
-      ans=sum;
-
-    }
+        for (j = 0; j < drives.size(); j++)
+        {
+            sum = keyboards[i] + drives[j];
+            if (sum <= b && sum > ans)
+                ans = sum;
+        }
     }
     return ans;
 }
 
 int main()
 {
-    ofstream fout(getenv("OUTPUT_PATH"));
+    ofstream fout;
+    ostream *out_stream = nullptr;
+    if (const char *output_path = getenv("OUTPUT_PATH"))
+    {
+        fout.open(output_path);
+        if (!fout)
+        {
+            cerr << "Failed to open OUTPUT_PATH for writing" << endl;
+            return 1;
+        }
+        out_stream = &fout;
+    }
+    else
+    {
+        out_stream = &cout;
+    }
 
     string bnm_temp;
-    getline(cin, bnm_temp);
+    if (!getline(cin, bnm_temp))
+    {
+        (*out_stream) << -1 << "\n";
+        if (fout.is_open())
+            fout.close();
+        return 0;
+    }
 
     vector<string> bnm = split_string(bnm_temp);
 
-    int b = stoi(bnm[0]);
-
-    int n = stoi(bnm[1]);
+    if (bnm.size() < 3)
+    {
+        // malformed first line: cannot parse budget, n, m
+        (*out_stream) << -1 << "\n";
+        if (fout.is_open())
+            fout.close();
+        return 0;
+    }
 
-    int m = stoi(bnm[2]);
+    int b = 0, n = 0, m = 0;
+    try
+    {
+        b = stoi(bnm[0]);
+        n = stoi(bnm[1]);
+        m = stoi(bnm[2]);
+    }
+    catch (...)
+    {
+        // malformed numbers
+        (*out_stream) << -1 << "\n";
+        if (fout.is_open())
+            fout.close();
+        return 0;
+    }
 
     string keyboards_temp_temp;
-    getline(cin, keyboards_temp_temp);
+    if (!getline(cin, keyboards_temp_temp))
+    {
+        (*out_stream) << -1 << "\n";
+        if (fout.is_open())
+            fout.close();
+        return 0;
+    }
 
     vector<string> keyboards_temp = split_string(keyboards_temp_temp);
 
-    vector<int> keyboards(n);
-
-    for (int keyboards_itr = 0; keyboards_itr < n; keyboards_itr++) {
-        int keyboards_item = stoi(keyboards_temp[keyboards_itr]);
-
-        keyboards[keyboards_itr] = keyboards_item;
+    // safely parse the keyboard prices; ignore malformed tokens
+    vector<int> keyboards;
+    keyboards.reserve(keyboards_temp.size());
+    for (const string &tok : keyboards_temp)
+    {
+        try
+        {
+            keyboards.push_back(stoi(tok));
+        }
+        catch (...)
+        {
+            // skip malformed token
+        }
     }
 
     string drives_temp_temp;
-    getline(cin, drives_temp_temp);
+    if (!getline(cin, drives_temp_temp))
+    {
+        (*out_stream) << -1 << "\n";
+        if (fout.is_open())
+            fout.close();
+        return 0;
+    }
 
     vector<string> drives_temp = split_string(drives_temp_temp);
 
-    vector<int> drives(m);
-
-    for (int drives_itr = 0; drives_itr < m; drives_itr++) {
-        int drives_item = stoi(drives_temp[drives_itr]);
-
-        drives[drives_itr] = drives_item;
+    // safely parse the drive prices; ignore malformed tokens
+    vector<int> drives;
+    drives.reserve(drives_temp.size());
+    for (const string &tok : drives_temp)
+    {
+        try
+        {
+            drives.push_back(stoi(tok));
+        }
+        catch (...)
+        {
+            // skip malformed token
+        }
     }
 
     /*
@@ -72,38 +138,27 @@ int main()
 
     int moneySpent = getMoneySpent(keyboards, drives, b);
 
-    fout << moneySpent << "\n";
+    (*out_stream) << moneySpent << "\n";
 
-    fout.close();
+    if (fout.is_open())
+        fout.close();
 
     return 0;
 }
 
-vector<string> split_string(string input_string) {
-    string::iterator new_end = unique(input_string.begin(), input_string.end(), [] (const char &x, const char &y) {
-        return x == y and x == ' ';
-    });
-
-    input_string.erase(new_end, input_string.end());
-
-    while (input_string[input_string.length() - 1] == ' ') {
-        input_string.pop_back();
-    }
-
+vector<string> split_string(string input_string)
+{
+    // Use istringstream to safely split on whitespace. This handles empty strings
+    // and any amount of whitespace between tokens without manual indexing.
     vector<string> splits;
-    char delimiter = ' ';
-
-    size_t i = 0;
-    size_t pos = input_string.find(delimiter);
+    if (input_string.empty())
+        return splits;
 
-    while (pos != string::npos) {
-        splits.push_back(input_string.substr(i, pos - i));
-
-        i = pos + 1;
-        pos = input_string.find(delimiter, i);
+    istringstream iss(input_string);
+    string token;
+    while (iss >> token)
+    {
+        splits.push_back(token);
     }
-
-    splits.push_back(input_string.substr(i, min(pos, input_string.length()) - i + 1));
-
     return splits;
 }