Merge pull request #150 from nik132-eng/patch-3

Create NextGreaterElement.java

Author: SarthakKeshari

LeetCode/NextGreaterElement.java

@@ -0,0 +1,68 @@
+//Given a positive integer n, find the smallest integer which has exactly 
+//the same digits existing in the integer n and is greater in value than n. 
+//If no such positive integer exists, return -1.
+
+//Note that the returned integer should fit in 32-bit integer,
+//if there is a valid answer but it does not fit in 32-bit integer, return -1.
+
+//Example 1:
+
+//Input: n = 12
+//Output: 21
+
+//Example 2:
+
+//Input: n = 21
+//Output: -1
+
+import java.util.Scanner;
+
+public class NextGreaterElement {
+
+	public static void main(String[] args) {
+		Scanner sc = new Scanner(System.in);
+		
+		int n = sc.nextInt();
+		long ans = nextGreaterElement(n);
+		System.out.println(ans);
+	}
+
+	private static long nextGreaterElement(int n) {
+//		convert interger to string and than string to character array
+		char arr[] = (Integer.toString(n)).toCharArray();
+		
+//		firstly find first lower element from left
+		int i = arr.length-2;
+		while(i>=0 && arr[i]>=arr[i+1])
+			i--;
+//		according top test case returning the -1
+		if(i==-1)
+			return -1;
+		
+		int k = arr.length-1;
+		while(arr[i]>=arr[k]) 
+			k--;
+//		swap the values of ith and kth
+		  char temp = arr[i];
+	        arr[i] = arr[k];
+	        arr[k] = temp;
+		
+//	      Storing the values of 0 to i in res
+	      String res = "";
+	      for(int j=0;j<=i;j++) 
+	    	  res+=arr[j];
+//		  for nearest greater integer store it in the reverse order 
+	      for(int j=arr.length-1;j>i;j--)
+	    	  res+=arr[j];
+	      
+	      
+//	      typecast to Long
+	      long ans = Long.parseLong(res);  
+	      if(ans<=2147483647)
+		      return (int) ans; 
+	        else
+	            return -1;
+	      
+	}
+
+}