Add Josephus Problem in C++ (Fixes #3332)

archive/c/c-plus-plus/josephus-problem.cpp

@@ -0,0 +1,47 @@
+#include <iostream>
+#include <stdexcept>
+#include <vector>
+using namespace std;
+
+void josephus(int n, int k) {
+    vector<int> people;
+    for (int i = 1; i <= n; ++i) {
+        people.push_back(i);
+    }
+
+    int index = 0;
+    while (people.size() > 1) {
+        cout << "[" << people[0];
+        for (size_t i = 1; i < people.size(); ++i) {
+            cout << ", " << people[i];
+        }
+        cout << "] " << (k - 1) << " " << index << endl;
+        index = (index + k - 1) % people.size();
+        people.erase(people.begin() + index);
+        if (index == people.size()) index = 0;
+    }
+    cout << people[0] << endl;
+}
+
+int main(int argc, char* argv[]) {
+    if (argc != 3) {
+        cerr << "Usage: please input the total number of people and number of people to skip.\n";
+        return 1;
+    }
+    try {
+        int n = stoi(argv[1]);
+        int k = stoi(argv[2]);
+        if (n <= 0 || k <= 0) {
+            cerr << "Usage: please input the total number of people and number of people to skip.\n";
+            return 1;
+        }
+        josephus(n, k);
+        return 0;
+    } catch (const invalid_argument&) {
+        cerr << "Usage: please input the total number of people and number of people to skip.\n";
+        return 1;
+    } catch (const out_of_range&) {
+        cerr << "Usage: please input the total number of people and number of people to skip.\n";
+        return 1;
+    }
+}