Add Challenge #213[Easy]

Author: jorgegil96

Java/Easy/CARule90.java

@@ -0,0 +1,55 @@
+// Created by /u/jorgegil96 on Reddit
+// Challenge #213 [Easy] Cellular Automata: Rule 90
+// https://www.reddit.com/r/dailyprogrammer/comments/3jz8tt/20150907_challenge_213_easy_cellular_automata/
+
+public class CARule90 {
+	public static void states(String input, StringBuilder sb) {
+		int before, after;
+		for (int i = 0; i < input.length(); i++) {
+			before = 0;
+			after = 0;
+			if (i == 0) {
+				after = Character.getNumericValue(input.charAt(i + 1));
+			}
+			else if (i == input.length() - 1) {
+				before = Character.getNumericValue(input.charAt(i - 1));
+			}
+			else {
+				before = Character.getNumericValue(input.charAt(i - 1));
+				after = Character.getNumericValue(input.charAt(i + 1));
+			}
+			if ((before + after) % 2 == 0) {
+				System.out.print(" ");
+				sb.setCharAt(i, '0');
+			}
+			else{
+				System.out.print("X");
+				sb.setCharAt(i, '1');
+			}
+		}
+	}
+
+	public static void main(String[] args) {
+		String input = "00000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000";
+		StringBuilder sb = new StringBuilder(input);
+
+		int n = 25;
+
+		for (int i = 0; i < input.length(); i++)
+			if (input.charAt(i) == '0')
+				System.out.print(' ');
+			else
+				System.out.print('X');
+
+		System.out.println("");
+
+		for (int i = 0; i < n; i++){
+			states(sb.toString(), sb);
+			if (!sb.toString().contains("1")){
+				break;
+			}
+			System.out.println("");
+		}
+
+	}
+}