Add implementation for absolute permutation algorithm

This commit introduces a complete solution for generating absolute permutations based on the input parameters `n` and `k`. It accounts for edge cases such as when `k` is zero or when a valid permutation is impossible. Additionally, helper functions for input trimming and parsing are included.

Author: holman57

AbsolutePermutation.cpp

@@ -0,0 +1,124 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+string ltrim(const string &);
+string rtrim(const string &);
+vector<string> split(const string &);
+
+/*
+ * Complete the 'absolutePermutation' function below.
+ *
+ * The function is expected to return an INTEGER_ARRAY.
+ * The function accepts following parameters:
+ *  1. INTEGER n
+ *  2. INTEGER k
+ */
+
+vector<int> absolutePermutation(int n, int k) {
+    // Case when k is 0, return the identity permutation
+    if (k == 0) {
+        vector<int> permutation(n);
+        iota(permutation.begin(), permutation.end(), 1);
+        return permutation;
+    }
+
+    // If n is not divisible by 2 * k, a valid permutation is not possible
+    if (n % (2 * k) != 0)
+        return {-1};
+
+    vector<int> permutation;
+    bool add = true;
+
+    // Iterate through numbers and alternate between adding and subtracting k
+    for (int i = 1; i <= n; ++i) {
+        if (add) {
+            permutation.push_back(i + k);
+        } else {
+            permutation.push_back(i - k);
+        }
+
+        // Flip `add` every k steps
+        if (i % k == 0) {
+            add = !add;
+        }
+    }
+
+    return permutation;
+}
+
+int main()
+{
+    ofstream fout(getenv("OUTPUT_PATH"));
+
+    string t_temp;
+    getline(cin, t_temp);
+
+    int t = stoi(ltrim(rtrim(t_temp)));
+
+    for (int t_itr = 0; t_itr < t; t_itr++) {
+        string first_multiple_input_temp;
+        getline(cin, first_multiple_input_temp);
+
+        vector<string> first_multiple_input = split(rtrim(first_multiple_input_temp));
+
+        int n = stoi(first_multiple_input[0]);
+
+        int k = stoi(first_multiple_input[1]);
+
+        vector<int> result = absolutePermutation(n, k);
+
+        for (size_t i = 0; i < result.size(); i++) {
+            fout << result[i];
+
+            if (i != result.size() - 1) {
+                fout << " ";
+            }
+        }
+
+        fout << "\n";
+    }
+
+    fout.close();
+
+    return 0;
+}
+
+string ltrim(const string &str) {
+    string s(str);
+
+    s.erase(
+            s.begin(),
+            find_if(s.begin(), s.end(), not1(ptr_fun<int, int>(isspace)))
+    );
+
+    return s;
+}
+
+string rtrim(const string &str) {
+    string s(str);
+
+    s.erase(
+            find_if(s.rbegin(), s.rend(), not1(ptr_fun<int, int>(isspace))).base(),
+            s.end()
+    );
+
+    return s;
+}
+
+vector<string> split(const string &str) {
+    vector<string> tokens;
+
+    string::size_type start = 0;
+    string::size_type end = 0;
+
+    while ((end = str.find(" ", start)) != string::npos) {
+        tokens.push_back(str.substr(start, end - start));
+
+        start = end + 1;
+    }
+
+    tokens.push_back(str.substr(start));
+
+    return tokens;
+}