Merge pull request #2078 from saip7795/sp/combination-sum-ii

Create: 0040-Combination-Sum-II.rb

Author: saip7795

Diff for: ruby/0040-combination-sum-ii.rb

@@ -0,0 +1,31 @@
+def combination_sum2(candidates, target)
+    @candidates = candidates
+    @candidates.sort!
+    @result = []
+
+    def backtrack (cur,pos,target)
+        @result.append(cur.dup()) if target == 0
+        return if target <=0
+
+        prev = -1
+
+        (pos..@candidates.length-1).each do |i|
+            next if @candidates[i] == prev
+
+            cur.append(@candidates[i])
+
+            backtrack(cur,i+1,target-@candidates[i])
+
+            cur.pop()
+
+            prev = @candidates[i]
+
+        end
+
+    end
+    backtrack([],0,target)
+
+    return @result
+
+    
+end