Added 1 solution & modified 2 solutions

Author: varunu28

Easy/Sort Integers by The Number of 1 Bits.java

@@ -1,22 +1,10 @@
 class Solution {
   public int[] sortByBits(int[] arr) {
-    PriorityQueue<Integer> pq = new PriorityQueue<>(new Comparator<Integer>(){
-      public int compare(Integer o1, Integer o2) {
-        int c = Integer.bitCount(o1) - Integer.bitCount(o2);
-        if (c != 0) {
-          return c;
-        }
-        return o1 - o2;
-      }
-    });
-    for (int num : arr) {
-      pq.add(num);
-    }
-    int[] ans = new int[arr.length];
-    int idx = 0;
-    while (!pq.isEmpty()) {
-      ans[idx++] = pq.poll();
-    }
-    return ans;
+    return Arrays.stream(arr).boxed()
+        .sorted(Comparator.comparingInt(Integer::bitCount).thenComparingInt(o -> o))
+        .collect(Collectors.toList())
+        .stream()
+        .mapToInt(Integer::intValue)
+        .toArray();
   }
 }

Medium/Capacity To Ship Packages Within D Days.java

@@ -0,0 +1,29 @@
+class Solution {
+  public int shipWithinDays(int[] weights, int D) {
+    int maxWeight = weights[0];
+    int totalWeight = 0;
+    for (int weight : weights) {
+      maxWeight = Math.max(maxWeight, weight);
+      totalWeight += weight;
+    }
+    while (maxWeight < totalWeight) {
+      int midWeight = (maxWeight + totalWeight) / 2;
+      int need = 1;
+      int curr = 0;
+      for (int weight : weights) {
+        if (curr + weight > midWeight) {
+            need += 1;
+            curr = 0;
+        }
+        curr += weight;
+      }
+      if (need > D) {
+        maxWeight = midWeight + 1;
+      }
+      else {
+        totalWeight = midWeight;
+      }
+    }
+    return maxWeight;
+  }
+}

Medium/Insert into a Binary Search Tree.java

@@ -4,24 +4,26 @@
  *     int val;
  *     TreeNode left;
  *     TreeNode right;
- *     TreeNode(int x) { val = x; }
+ *     TreeNode() {}
+ *     TreeNode(int val) { this.val = val; }
+ *     TreeNode(int val, TreeNode left, TreeNode right) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
  * }
  */
 class Solution {
-    public TreeNode insertIntoBST(TreeNode root, int val) {
-        if (root == null) {
-            root = new TreeNode(val);
-            return root;
-        }
-        
-        if (root.val < val) {
-            root.right = insertIntoBST(root.right, val);
-        }
-        
-        if (root.val > val) {
-            root.left = insertIntoBST(root.left, val);
-        }
-        
-        return root;
+  public TreeNode insertIntoBST(TreeNode root, int val) {
+    if (root == null) {
+      return new TreeNode(val);
     }
+    if (root.val < val) {
+      root.right = insertIntoBST(root.right, val);
+    }
+    else {
+      root.left = insertIntoBST(root.left, val);
+    }
+    return root;
+  }
 }