[염혜정] 2026/10/01

leetcode3/염혜정/1219. Path with Maximum Gold.java

@@ -0,0 +1,34 @@
+// dfs + 백트래킹
+
+class Solution {
+    int[] dx = {-1, 1, 0, 0};
+    int[] dy = {0, 0, -1, 1};
+
+    public int getMaximumGold(int[][] grid) {
+        int max = 0;
+        for (int i = 0; i<grid.length; i++) {
+            for (int k = 0; k<grid[0].length; k++) {
+                if (grid[i][k] == 0) continue;
+                max = Math.max(max, dfs(grid, i, k));
+            }
+        }
+        return max;
+    }
+
+    int dfs(int[][] grid, int x, int y) {
+        if (x<0 || y<0 || x>=grid.length || y>=grid[0].length 
+            || grid[x][y] == 0) return 0;
+
+        int temp = grid[x][y];
+        grid[x][y] = 0;
+
+        int max = 0;
+        for (int i = 0; i<4; i++) {
+            max = Math.max(max, dfs(grid, x+dx[i], y+dy[i]));
+        }
+        grid[x][y] = temp;
+
+        return max + temp;
+    }
+
+}

leetcode3/염혜정/Code Testcase Testcase Test Result 543. Diameter of Binary Tree.java

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+// 재귀함수
+// O(n)
+
+class Solution {
+    int max;
+    public int diameterOfBinaryTree(TreeNode root) {
+        max = 0;
+        depth(root);
+        return max;
+    }
+
+    int depth(TreeNode node) {
+        if (node == null) return 0;
+
+        int left = depth(node.left);
+        int right = depth(node.right);
+        max = Math.max(max, left + right);
+
+        return Math.max(left, right) + 1;
+    }
+}