[김대원] Day16

leetcode2/1easy/김대원/Q892.java

@@ -0,0 +1,35 @@
+class Solution {
+    public int surfaceArea(int[][] grid) {
+        int total = 0;
+        int n = grid.length;
+        int m = grid[0].length;
+        Queue<int[]> pq = new PriorityQueue<>((a, b) -> b[2] - a[2]);
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                total += grid[i][j] * 4 + 2;
+                pq.offer(new int[] {i, j, grid[i][j]});
+            }
+        }
+
+        int gap = 0;
+        int[] dx = {-1, 0, 1, 0};
+        int[] dy = {0, 1, 0, -1};
+        while (!pq.isEmpty()) {
+            int[] now = pq.poll();
+            int x = now[0];
+            int y = now[1];
+            int val = now[2];
+
+            for (int i = 0; i < 4; i++) {
+                int nx = x + dx[i];
+                int ny = y + dy[i];
+
+                if (nx >= 0 && nx < n && ny >= 0 && ny < m) {
+                    if (val > grid[nx][ny]) gap += (val - grid[nx][ny]);
+                }
+            }
+        }
+
+        return total - gap;
+    }
+}

leetcode2/2medium/김대원/Q117.java

@@ -0,0 +1,59 @@
+/*
+// Definition for a Node.
+class Node {
+    public int val;
+    public Node left;
+    public Node right;
+    public Node next;
+
+    public Node() {}
+
+    public Node(int _val) {
+        val = _val;
+    }
+
+    public Node(int _val, Node _left, Node _right, Node _next) {
+        val = _val;
+        left = _left;
+        right = _right;
+        next = _next;
+    }
+};
+*/
+
+class Solution {
+
+    static Map<Integer, Queue<Node>> map;
+
+    public Node connect(Node root) {
+        map = new HashMap<>();
+        searchDepth(0, root);
+        return helper(0, root);
+    }
+
+    private Node helper(int depth, Node root) {
+        if (root == null) return null;
+        if (!map.get(depth).isEmpty()) {
+            Node n = map.get(depth).poll();
+            root.next = n;
+        }
+
+        helper(depth + 1, root.left);
+        helper(depth + 1, root.right);
+
+        return root;
+    }
+
+    private void searchDepth(int depth, Node root) {
+        if (root == null) return;
+
+        if (!map.containsKey(depth)) {
+            map.put(depth, new ArrayDeque<>());
+        } else {
+            map.get(depth).add(root);
+        }
+
+        searchDepth(depth + 1, root.left);
+        searchDepth(depth + 1, root.right);
+    }
+}