Merge pull request #83 from NishantTanwar/master

Added Permutations of String problem in Backtrack Section

Backtrack/permutations_of_string.cpp

@@ -0,0 +1,47 @@
+// Solution for printing all the permutations of a string.
+#include<bits/stdc++.h>
+
+/* Function to swap values at two pointers */
+void swap(char *x, char *y)
+{
+    char temp;
+    temp = *x;
+    *x = *y;
+    *y = temp;
+}
+
+/* Function to print permutations of string
+   This function takes three parameters:
+   1. String
+   2. Starting index of the string
+   3. Ending index of the string. */
+void permute(char *a, int l, int r)
+{
+    int i;
+    if (l == r)
+        cout<<a;
+    else
+    {
+        for (i = l; i <= r; i++)
+        {
+            swap((a+l), (a+i));
+            permute(a, l+1, r);
+            swap((a+l), (a+i)); //backtrack
+        }
+    }
+}
+
+int main()
+{
+    char str[] = "ABC";
+    int n = strlen(str);
+    permute(str, 0, n-1);
+    return 0;
+}
+/*Output
+ABC
+ACB
+BAC
+BCA
+CBA
+CAB*/