LC#290 convert number in linkedlist nodes as whole to decimal from binary

Author: NirmalSilwal

Leetcode/leetcodeTags/LinkedList/ConvertBinaryNumToIntegerInLinkedList290.java

@@ -0,0 +1,61 @@
+package LinkedList;
+
+public class ConvertBinaryNumToIntegerInLinkedList290 {
+
+	public class ListNode {
+		int val;
+		ListNode next;
+
+		ListNode() {
+		}
+
+		ListNode(int val) {
+			this.val = val;
+		}
+
+		ListNode(int val, ListNode next) {
+			this.val = val;
+			this.next = next;
+		}
+	}
+
+	public int getDecimalValue(ListNode head) {
+
+		StringBuilder sb = new StringBuilder("");
+		ListNode temp = head;
+
+		while (temp != null) {
+			sb.append(temp.val);
+			temp = temp.next;
+		}
+
+//	 	long binaryValue = Long.parseLong(sb.toString());
+//	    int decimal = getDecimalFromBinary(binaryValue);
+
+		return Integer.parseInt(sb.toString(), 2);
+	}
+
+	/*
+	 * private static int getDecimalFromBinary(Long binaryValue) { int total = 0;
+	 * int power = 0;
+	 * 
+	 * while (binaryValue != 0) { long rem = binaryValue % 10; total += (rem *
+	 * Math.pow(2, power++)); binaryValue /= 10; }
+	 * 
+	 * return total; }
+	 */
+
+	//2nd approach
+	public int getDecimalValue2(ListNode head) {
+		int ans = 0;
+		ListNode temp = head;
+
+		while (temp != null) {
+			ans *= 2;
+			ans += temp.val;
+			temp = temp.next;
+		}
+
+		return ans;
+	}
+}