From 972f30d9373e41ec253be5ed8e42199fef2f0b7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20D=C4=85bkowski?= <rafdab@st.amu.edu.pl>
Date: Thu, 31 May 2018 06:20:14 +0000
Subject: [PATCH] =?UTF-8?q?Prze=C5=9Blij=20pliki=20do=20''?=
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---
 Main.java | 44 +++++++++++++++++++++++++++
 Ring.java | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 Main.java
 create mode 100644 Ring.java

diff --git a/Main.java b/Main.java
new file mode 100644
index 0000000..53cb448
--- /dev/null
+++ b/Main.java
@@ -0,0 +1,44 @@
+import java.util.Arrays;
+import java.util.Scanner;
+
+public class Main {
+
+    public static void main(String[] args) {
+        int n;
+        if (args.length < 1) {
+            n = -1;
+            Scanner scanner = new Scanner(System.in);
+            while (n < 2) {
+                System.out.print("n = ");
+                n = scanner.nextInt();
+            }
+        } else { n = Integer.parseInt(args[0]); }
+
+        Ring r = new Ring(n);
+
+        r.wyznaczOdwracalne();
+        r.wyznaczDzielniki();
+        r.wyznaczNil();
+        r.wyznaczId();
+
+        System.out.println("elementy odwracalne (" + r.odwracalne.size() + "):");
+        for (int i: r.odwracalne) {
+            System.out.print(i + ", ");
+        }
+        System.out.println();
+        System.out.println("dzielniki zera (" + r.dzielniki.size() + "):");
+        for (int i: r.dzielniki) {
+            System.out.print(i + ", ");
+        }
+        System.out.println();
+        System.out.println("elementy nilpotentne (" + r.nilpotentne.size() + "):");
+        for (int i: r.nilpotentne) {
+            System.out.print(i + ", ");
+        }
+        System.out.println();
+        System.out.println("elementy idempotentne (" + r.idempotentne.size() + "):");
+        for (int i: r.idempotentne) {
+            System.out.print(i + ", ");
+        }
+    }
+}
diff --git a/Ring.java b/Ring.java
new file mode 100644
index 0000000..5a29b91
--- /dev/null
+++ b/Ring.java
@@ -0,0 +1,89 @@
+import java.util.ArrayList;
+
+public class Ring {
+    int n;
+    ArrayList<Integer> odwracalne;
+    ArrayList<Integer> dzielniki;
+    ArrayList<Integer> nilpotentne;
+    ArrayList<Integer> idempotentne;
+
+    public Ring(int n) {
+        this.n = n;
+        odwracalne = new ArrayList<>();
+        dzielniki = new ArrayList<>();
+        nilpotentne = new ArrayList<>();
+        idempotentne = new ArrayList<>();
+    }
+    private int nwd(int a, int b){
+        while (a != b){
+            if (a > b) a -=b;
+            else b -= a;
+        }
+        return a;
+    }
+
+    private int phi(int a){
+        float result = a;
+        for (int p = 2; p * p <= a; ++p) {
+            if (a % p == 0) {
+                while (a % p == 0)
+                    a /= p;
+                result *= (1.0 - (1.0 / (float)p));
+            }
+        }
+        if (a > 1)
+            result *= (1.0 - (1.0 / (float)a));
+
+        return (int)result;
+    }
+
+    static int modularPower(int x, int y, int p){
+        int res = 1;
+        x = x % p;
+
+        while (y > 0){
+            if((y & 1)==1) res = (res * x) % p;
+            y = y >> 1;
+            x = (x * x) % p;
+        }
+        return res;
+    }
+
+    void wyznaczOdwracalne(){
+        for (int i = 1; i < n; ++i){
+            if (nwd(i, n) == 1) odwracalne.add(i);
+        }
+    }
+
+    void wyznaczDzielniki(){
+        for (int i = 1; i < n; ++i){
+            for (int j = 1; j < n; ++j){
+                if(((i * j) % n) == 0){
+                    dzielniki.add(i);
+                    break;
+                }
+            }
+        }
+    }
+
+    void wyznaczNil(){
+        for (int i = 1; i < n; ++i){
+            for (int j = 1; j <= phi(n); ++j){
+                if (modularPower(i, j, n) == 0){
+                    nilpotentne.add(i);
+                    break;
+                }
+            }
+        }
+    }
+
+    void wyznaczId(){
+        int pow;
+        for (int i = 0; i < n; ++i){
+            pow = (i * i) % n;
+            if (pow == i){
+                idempotentne.add(i);
+            }
+        }
+    }
+}