Hackerrank cpp 20190330 1

hackerrank/array/min_swaps1.cpp

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+
+// Original Link 
+// https://www.hackerrank.com/challenges/minimum-swaps-2/problem
+
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<string> split_string(string);
+
+
+
+
+///////////////// SOLUTION //////////////////
+
+// Idea is to solve it with a recurrent function which iteratively performs greedy swaps 
+
+void swap(vector<int>& v, const unsigned int a, const unsigned int b)
+{
+    int temp; 
+    temp = v[a];
+    v[a] = v[b]; 
+    v[b] = temp; 
+}
+
+unsigned int search(const vector<int>& v, const unsigned int p, const int q)
+{
+    for(unsigned int i=p; i<v.size(); ++i) if(v[i] == q) return i; 
+    throw std::runtime_error("Not Found"); 
+}
+
+int solve(vector<int>& v, const unsigned int i, const unsigned int cont)
+{
+    // Recursion Ending Conditions 
+    if(i == v.size()-1) return cont; 
+
+    // Expected Number 
+    const int n = i+1; 
+    if(v[i] == n) return solve(v, i+1, cont); 
+    else 
+    {
+        const unsigned int j = search(v, i+1, n); 
+        swap(v, i, j); 
+        return solve(v, i+1, cont+1); 
+    }
+}
+
+// Complete the minimumSwaps function below.
+int minimumSwaps(vector<int> arr) {
+    return solve(arr, 0, 0); 
+}
+
+
+
+
+/////////////////////////////////////////
+
+int main()
+{
+    ofstream fout(getenv("OUTPUT_PATH"));
+
+    int n;
+    cin >> n;
+    cin.ignore(numeric_limits<streamsize>::max(), '\n');
+
+    string arr_temp_temp;
+    getline(cin, arr_temp_temp);
+
+    vector<string> arr_temp = split_string(arr_temp_temp);
+
+    vector<int> arr(n);
+
+    for (int i = 0; i < n; i++) {
+        int arr_item = stoi(arr_temp[i]);
+
+        arr[i] = arr_item;
+    }
+
+    int res = minimumSwaps(arr);
+
+    fout << res << "\n";
+
+    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> splits;
+    char delimiter = ' ';
+
+    size_t i = 0;
+    size_t pos = input_string.find(delimiter);
+
+    while (pos != string::npos) {
+        splits.push_back(input_string.substr(i, pos - i));
+
+        i = pos + 1;
+        pos = input_string.find(delimiter, i);
+    }
+
+    splits.push_back(input_string.substr(i, min(pos, input_string.length()) - i + 1));
+
+    return splits;
+}

hackerrank/array/readme.md

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+
+# Overview 
+
+Some Hackerrank Related Exercises 
+
+Minimum Swaps 2
+- [Def](https://www.hackerrank.com/challenges/minimum-swaps-2/problem)
+- [Sol](min_swaps1.cpp)
+- Hint 
+  - Solved used recursion and in place swap 
+