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+#!/usr/bin/env python3
+
+# Challenge 074
+#
+# TASK #2 > FNR Character
+# Submitted by: Mohammad S Anwar
+# You are given a string $S.
+#
+# Write a script to print the series of first non-repeating character (left
+# -> right) for the given string. Print # if none found.
+#
+# Example 1
+# Input: $S = 'ababc'
+# Output: 'abb#c'
+# Pass 1: "a", the FNR character is 'a'
+# Pass 2: "ab", the FNR character is 'b'
+# Pass 3: "aba", the FNR character is 'b'
+# Pass 4: "abab", no FNR found, hence '#'
+# Pass 5: "ababc" the FNR character is 'c'
+#
+# Example 2
+# Input: $S = 'xyzzyx'
+# Output: 'xyzyx#'
+# Pass 1: "x", the FNR character is "x"
+# Pass 2: "xy", the FNR character is "y"
+# Pass 3: "xyz", the FNR character is "z"
+# Pass 4: "xyzz", the FNR character is "y"
+# Pass 5: "xyzzy", the FNR character is "x"
+# Pass 6: "xyzzyx", no FNR found, hence '#'
+
+import sys
+
+def lnr_char(s):
+    out = ""
+    seen = {}
+    for i in range(len(s)):
+        ch = s[i]
+        if ch in seen:
+            seen[ch] += 1
+        else:
+            seen[ch] = 1
+        found = False
+        for j in range(i+1)[::-1]:
+            ch = s[j]
+            if ch in seen and seen[ch] == 1:
+                out += ch
+                found = True
+                break
+        if not found:
+            out += "#"
+    return out
+
+s = sys.argv[1]
+print(lnr_char(s))