添加完成的题目

Author: YorkPeng

394.字符串解码.java

@@ -0,0 +1,58 @@
+import java.util.ArrayList;
+import java.util.Stack;
+
+/*
+ * @lc app=leetcode.cn id=394 lang=java
+ *
+ * [394] 字符串解码
+ */
+
+// @lc code=start
+class Solution {
+    public String decodeString(String s) {
+        Stack<String> stack = new Stack<>();
+        ArrayList<Integer> list = new ArrayList<>();
+        char[] c = s.toCharArray();
+        StringBuilder temp = new StringBuilder();
+        StringBuilder number = new StringBuilder();
+        for(int i = 0; i < c.length;i++){
+            if(c[i]>='0' && c[i] <= '9'){
+                number.append(String.valueOf(c[i]));
+            }else if (c[i] == '['){
+                list.add(Integer.valueOf(number.toString()));
+                number = new StringBuilder();
+                stack.push(String.valueOf(c[i]));
+            }else if ((c[i] >='a' && c[i] <='z') || (c[i] >= 'A' && c[i]<='Z')){
+                stack.push(String.valueOf(c[i]));
+            }else if(c[i] == ']'){
+                temp = new StringBuilder();
+                ArrayList<String> holder = new ArrayList<>();
+                StringBuilder sb = new StringBuilder();
+                while(!"[".equals(stack.peek())){
+                    holder.add(stack.pop());
+                }
+                stack.pop();
+                for(int j = holder.size()-1;j>=0;j--){
+                    sb.append(holder.get(j));
+                }
+                int times = list.remove(list.size()-1);
+                for(int j = 0; j < times; j++){
+                    temp.append(sb);
+                }
+                stack.push(temp.toString());
+                temp = new StringBuilder();
+            }
+        }
+        temp = new StringBuilder();
+        ArrayList<String> holder2 = new ArrayList<>();
+        while(!stack.isEmpty()){
+            holder2.add(stack.pop());
+        }
+        for(int j = holder2.size()-1;j>=0;j--){
+            temp.append(holder2.get(j));
+        }
+        return temp.toString();
+    }
+}
+// @lc code=end
+

662.二叉树最大宽度.java

@@ -0,0 +1,55 @@
+import java.util.LinkedList;
+import java.util.Queue;
+
+import javax.swing.tree.TreeNode;
+
+/*
+ * @lc app=leetcode.cn id=662 lang=java
+ *
+ * [662] 二叉树最大宽度
+ */
+
+// @lc code=start
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode(int x) { val = x; }
+ * }
+ */
+class Solution {
+    public int widthOfBinaryTree(TreeNode root) {
+        LinkedList<Integer> list = new LinkedList<>();
+        Queue<TreeNode> queue = new LinkedList<>();
+        if(root == null){
+            return 0;
+        }
+        queue.add(root);
+        list.add(1);
+        int result = 1;
+        while(!queue.isEmpty()){
+            int count = queue.size();
+            for(int i = 0 ; i < count;i++){
+                TreeNode temp = queue.poll();
+                int currentLevel = list.removeFirst();
+                if(temp.left != null){
+                    queue.add(temp.left);
+                    list.add(currentLevel*2);
+                }
+                if(temp.right != null){
+                    queue.add(temp.right);
+                    list.add(currentLevel*2+1);
+                }
+            }
+            if(list.size()>=2){
+            result = Math.max(result, list.getLast() - list.getFirst() +1);
+            }
+
+        }
+        return result;
+    }
+}
+// @lc code=end
+