diff --git a/container-with-most-water/jinhyungrhee.java b/container-with-most-water/jinhyungrhee.java
new file mode 100644
index 000000000..ab87840c3
--- /dev/null
+++ b/container-with-most-water/jinhyungrhee.java
@@ -0,0 +1,32 @@
+class Solution {
+
+    /**
+     * time-complexity : O(n)
+     * space-complexity : O(1)
+     */
+
+    public int maxArea(int[] height) {
+
+        int left = 0;
+        int right = height.length - 1;
+
+        int w = 0, h = 0, currSize = 0, maxSize = 0;
+
+        while (left < right) {
+
+            w = right - left;
+            h = Math.min(height[left], height[right]);
+
+            currSize = w * h;
+            maxSize = Math.max(currSize, maxSize);
+
+            if (height[left] < height[right]) {
+                left++;
+            } else {
+                right--;
+            }
+
+        }
+        return maxSize;
+    }
+}
diff --git a/design-add-and-search-words-data-structure/jinhyungrhee.java b/design-add-and-search-words-data-structure/jinhyungrhee.java
new file mode 100644
index 000000000..1cf377293
--- /dev/null
+++ b/design-add-and-search-words-data-structure/jinhyungrhee.java
@@ -0,0 +1,75 @@
+class TrieNode {
+    boolean word;
+    TrieNode[] children;
+
+    TrieNode() {
+        this.word = false;
+        this.children = new TrieNode[27];
+    }
+}
+
+class WordDictionary {
+    /**
+     * space-complexity : O(N * L) (w.c)
+     *  - N : 단어 수, L : 평균 길이
+     *  - 단어 하나 추가 시 최대 L개의 TrieNode 생성
+     *  - (w.c) 모든 단어가 중복 없이 추가되면 (N*L)개의 노드 필요
+     */
+    TrieNode root;
+    public WordDictionary() {
+        this.root = new TrieNode();
+    }
+
+    /**
+     * addWord() Time-complexity : O(L)
+     *  - 각 문자마다 TrieNode를 따라 내려가며 필요한 경우 새 노드 생성
+     *  - 한 단어당 최대 L개의 노드 생성 및 접근
+     */
+    public void addWord(String word) {
+
+        TrieNode curr = root;
+        for (char c : word.toCharArray()) {
+            if (curr.children[c - 'a'] == null) {
+                curr.children[c - 'a'] = new TrieNode();
+            }
+            curr = curr.children[c - 'a'];
+        }
+        curr.word = true;
+    }
+
+    /**
+     * search() Time-complexity :
+     *  - '.'가 없는 경우 : O(L)
+     *      -> 일반적인 문자는 한 경로만 탐색
+     *  - '.'가 있는 경우 : O(26^L) (w.c)
+     *      -> 현재 노드의 모든 자식에 대해 DFS 수행
+     *
+     */
+    public boolean search(String word) {
+        return dfs(word, 0, root);
+    }
+
+    public boolean dfs(String word, int index, TrieNode node) {
+
+        if (index == word.length()) {
+            return node.word;
+        }
+
+        char c = word.charAt(index);
+
+        if (c == '.') {
+            for (TrieNode child : node.children) {
+                if (child != null && dfs(word, index + 1, child)) {
+                    return true;
+                }
+            }
+            return false;
+
+        } else {
+
+            TrieNode next = node.children[c - 'a'];
+            return next != null && dfs(word, index + 1, next);
+
+        }
+    }
+}
diff --git a/longest-increasing-subsequence/jinhyungrhee.java b/longest-increasing-subsequence/jinhyungrhee.java
new file mode 100644
index 000000000..e5d5a6b64
--- /dev/null
+++ b/longest-increasing-subsequence/jinhyungrhee.java
@@ -0,0 +1,27 @@
+import java.util.*;
+class Solution {
+    /**
+     * time-complexity : O(n^2)
+     * space-complexity : O(n)
+     */
+    public int lengthOfLIS(int[] nums) {
+
+        int[] dp = new int[nums.length];
+        Arrays.fill(dp, 1);
+
+        for (int i = 1 ; i < nums.length; i++) {
+            for (int j = i; j >= 0; j--) {
+                if (nums[j] < nums[i]) {
+                    dp[i] = Math.max(dp[i], dp[j] + 1);
+                }
+            }
+        }
+
+        int maxVal = 0;
+        for (int num : dp) {
+            if (num > maxVal) maxVal = num;
+        }
+
+        return maxVal;
+    }
+}
diff --git a/spiral-matrix/jinhyungrhee.java b/spiral-matrix/jinhyungrhee.java
new file mode 100644
index 000000000..b119725af
--- /dev/null
+++ b/spiral-matrix/jinhyungrhee.java
@@ -0,0 +1,53 @@
+import java.util.*;
+class Solution {
+    /**
+     * time-complexity : O(n * m)
+     * space-complexity : O(1) (excluding the output List)
+     */
+    public List<Integer> spiralOrder(int[][] matrix) {
+
+        List<Integer> result = new ArrayList<>();
+
+        int left = 0;
+        int right = matrix[0].length - 1;
+        int top = 0;
+        int bottom = matrix.length - 1;
+
+        while (left <= right && top <= bottom) {
+
+            // 위쪽 행을 순회한 후, 상단 경계를 1 증가
+            for (int y = left; y <= right; y++) {
+                result.add(matrix[top][y]);
+            }
+            top++;
+
+            // 상단 인덱스가 하단 인덱스 보다 커지면 순회 중단
+            if (top > bottom) break;
+
+            // 우측 열을 순회한 후, 우측 경계를 1 감소
+            for (int x = top; x <= bottom; x++) {
+                result.add(matrix[x][right]);
+            }
+            right--;
+
+            // 우측 인덱스가 좌측 인덱스보다 작아지면 순회 중단
+            if (right < left) break;
+
+            // 아래쪽 행을 순회한 후, 하단 경계를 1 감소
+            for (int y = right; y >= left; y--) {
+                result.add(matrix[bottom][y]);
+            }
+            bottom--;
+
+            // 왼쪽 열을 순회한 후, 좌측 경계를 1 증가
+            for (int x = bottom; x >= top; x--) {
+                result.add(matrix[x][left]);
+            }
+            left++;
+
+        }
+        return result;
+
+    }
+
+}
diff --git a/valid-parentheses/jinhyungrhee.java b/valid-parentheses/jinhyungrhee.java
new file mode 100644
index 000000000..a60a05a74
--- /dev/null
+++ b/valid-parentheses/jinhyungrhee.java
@@ -0,0 +1,31 @@
+import java.util.*;
+class Solution {
+    /**
+     * time-complexity : O(n)
+     * space-complexity : O(n)
+     */
+    public boolean isValid(String s) {
+
+        Deque<Character> stack = new ArrayDeque<>();
+        Map<Character, Character> table = new HashMap<>();
+        table.put(')', '(');
+        table.put(']', '[');
+        table.put('}', '{');
+
+        for (int i = 0; i < s.length(); i++) {
+            if (table.containsKey(s.charAt(i))) {
+
+                if ((table.get(s.charAt(i))).equals(stack.peek())) {
+                    stack.pop();
+                } else {
+                    stack.push(s.charAt(i));
+                }
+
+            } else {
+                stack.push(s.charAt(i));
+            }
+        }
+
+        return stack.isEmpty();
+    }
+}