Added 3 solutions

varunu28 · varunu28 · commit 319cab923a73 · 2019-08-04T09:17:03.000-07:00
diff --git a/Medium/Decrease Elements To Make Array Zigzag.java b/Medium/Decrease Elements To Make Array Zigzag.java
@@ -0,0 +1,28 @@
+class Solution {
+    public int movesToMakeZigzag(int[] nums) {
+        return Math.min(calculateMove(nums, true), calculateMove(nums, false));
+    }
+    
+    private int calculateMove(int[] nums, boolean isEven) {
+        int count = 0;
+        
+        for (int i = (isEven ? 0 : 1); i < nums.length; i += 2) {
+            int curr = 0;
+            if (i + 1 < nums.length) {
+                if (nums[i] >= nums[i + 1]) {
+                    curr = nums[i] - nums[i + 1] + 1;
+                }
+            }
+            
+            if (i - 1 >= 0) {
+                if (nums[i] >= nums[i - 1]) {
+                    curr = Math.max(curr, nums[i] - nums[i - 1] + 1);
+                }
+            }
+            
+            count += curr;
+        }
+        
+        return count;
+    }
+}
diff --git a/Medium/Snapshot Array.java b/Medium/Snapshot Array.java
@@ -0,0 +1,45 @@
+class SnapshotArray {
+
+    int[] arr;
+    Map<Integer, Map<Integer, Integer>> map;
+    int count;
+    Map<Integer, Integer> temp;
+    public SnapshotArray(int length) {
+        arr = new int[length];
+        map = new HashMap<>();
+        count = 0;
+        temp = new HashMap<>();
+    }
+
+    public void set(int index, int val) {
+        arr[index] = val;
+        temp.put(index, val);
+    }
+
+    public int snap() {
+        map.put(count, new HashMap<>(temp));
+        int snapCount = count++;
+        temp = new HashMap<>();
+        return snapCount;
+    }
+
+    public int get(int index, int snap_id) {
+        while (snap_id >= 0) {
+            if (map.get(snap_id).containsKey(index)) {
+                return map.get(snap_id).get(index);
+            }
+
+            snap_id--;
+        }
+
+        return 0;
+    }
+}
+
+/**
+ * Your SnapshotArray object will be instantiated and called as such:
+ * SnapshotArray obj = new SnapshotArray(length);
+ * obj.set(index,val);
+ * int param_2 = obj.snap();
+ * int param_3 = obj.get(index,snap_id);
+ */
diff --git a/Medium/Total Hamming Distance.java b/Medium/Total Hamming Distance.java
@@ -0,0 +1,15 @@
+class Solution {
+    public int totalHammingDistance(int[] nums) {
+        int count = 0;        
+        for (int i = 0; i < 32; i++) {
+            int bitCount = 0;
+            for (int j = 0; j < nums.length; j++) {
+                bitCount += (nums[j] >> i) & 1;
+            }
+            
+            count += bitCount * (nums.length - bitCount);
+        }
+        
+        return count;
+    }
+}
