70 solution

#442/Solution.java

@@ -0,0 +1,16 @@
+/**
+ * https://leetcode.com/problems/find-all-duplicates-in-an-array/
+ */
+
+class Solution {
+	public List<Integer> findDuplicates(int[] nums) {
+		List<Integer> duplicates = new ArrayList<Integer>();
+		Set<Integer> noDupes = new HashSet<Integer>();
+        for (int i = 0; i < nums.length; i++){
+            if(noDupes.add(nums[i]) == false) {
+            	duplicates.add(nums[i]);
+            }
+        }
+        return duplicates;
+	}
+}

#70/Solution.java

@@ -0,0 +1,15 @@
+class Solution {
+    public int climbStairs(int n) {
+	    	if(n ==1) {
+	    		return n;
+	    	}
+	    	int first = 1;
+	    	int second = 2;
+	    	for (int i = 3; i <= n; i++) {
+	    		int third = first + second;
+	    		first = second;
+	    		second = third;
+	    	}
+	    	return second;
+	    }
+}