Merge pull request TheAlgorithms#1316 from joshiujjawal22/master

Adding 3 sum problem, array rotation

Others/3 sum.java

@@ -0,0 +1,60 @@
+package Others;
+
+import java.util.Scanner;
+import java.util.Arrays;
+
+/**
+ * To find triplet equals to given sum in complexity O(n*log(n))
+ * 
+ *
+ * Array must be sorted 
+ *
+ * @author Ujjawal Joshi
+ * @date 2020.05.18
+ *
+ * Test Cases:
+ 	Input:
+ *	6 //Length of array
+ 	12 3 4 1 6 9
+ 	target=24
+ *	Output:3 9 12
+ *	Explanation: There is a triplet (12, 3 and 9) present
+	in the array whose sum is 24. 
+ *
+ *
+
+ */
+
+
+class threesum{
+	public static void main(String args[])
+	{
+		Scanner sc =new Scanner(System.in);
+		int n=sc.nextInt(); //Length of an array
+
+		int a[]=new int[n];
+
+		for(int i=0;i<n;i++)
+		{
+			a[i]=sc.nextInt();
+		}
+		System.out.println("Target");
+		int n_find=sc.nextInt();
+
+		Arrays.sort(a);	// Sort the array if array is not sorted
+
+		for(int i=0;i<n;i++){	
+
+			int l=i+1,r=n-1;
+
+			while(l<r){
+				if(a[i]+a[l]+a[r]==n_find) {System.out.println(a[i]+" "+ a[l]+" "+a[r]);break;} //if you want all the triplets write l++;r--; insted of break; 
+				else if(a[i]+a[l]+a[r]<n_find) l++;
+				else r--;
+			}
+		}
+
+
+
+	}
+}

Others/Rotation of array without using extra space.java

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+package Others;
+
+import java.util.*;
+
+/**
+ * Rotation of array without using extra space
+ * 
+ *
+ * @author Ujjawal Joshi
+ * @date 2020.05.18
+ *
+ * Test Cases:
+
+ 	Input:
+ 	2 //Size of matrix
+	1 2
+ 	3 4
+ 	Output:
+ 	3 1
+ 	4 2
+ ------------------------------
+ 	Input:
+ 	3 //Size of matrix
+	1 2 3 
+	4 5 6
+	7 8 9  
+	Output:
+	7 4 1 
+	8 5 2
+	9 6 3
+ * 
+ */
+
+class main{
+	public static void main(String[] args)
+	{
+		Scanner sc=new Scanner(System.in);
+		int n=sc.nextInt();
+		int a[][]=new int[n][n];
+
+		for(int i=0;i<n;i++)
+		{
+			for(int j=0;j<n;j++)
+			{
+				a[i][j]=sc.nextInt();
+			}
+		}
+		int temp=0;
+
+		// Rotation of array by swapping their values
+		for(int i=0;i<n/2;i++)
+		{	
+			for(int j=i;j<n-i-1;j++)
+			{	
+				temp=a[i][j];
+				a[i][j]=a[n-j-1][i];
+				a[n-j-1][i]=a[n-i-1][n-j-1];
+				a[n-i-1][n-j-1]=a[j][n-i-1];
+				a[j][n-i-1]=temp;
+			}
+		}
+
+		// printing of sorted array
+    for(int i=0;i<n;i++){
+      for(int j=0;j<n;j++){
+         System.out.print(a[i][j]+" ");
+
+      }
+      System.out.println();
+    }
+
+  }
+
+
+}