diff --git a/coin-change/kimjunyoung90.java b/coin-change/kimjunyoung90.java
new file mode 100644
index 0000000000..77baa1a95c
--- /dev/null
+++ b/coin-change/kimjunyoung90.java
@@ -0,0 +1,28 @@
+import java.util.Arrays;
+
+class Solution {
+    //풀이 원리 = 특정 금액을 만들 때 최소 동전 수는 몇 개?
+    //예) 0원은 동전 0개
+    // 1원은 동전 1개
+    // 2원은 동전 1
+    public int coinChange(int[] coins, int amount) {
+        //불가능한 값
+        int max = amount + 1;
+        int[] dp = new int[amount + 1];
+        //최소 동전 수를 모두 불가능한 값으로 설정
+        Arrays.fill(dp, max);
+        dp[0] = 0;
+
+        //금액 1원 부터 계산
+        for (int i = 1; i <= amount; i++) {
+            //사용할 수 있는 동전을 꺼냄
+            for(int coin: coins) {
+                if (coin <= i) {
+                    dp[i] = Math.min(dp[i], dp[i - coin] + 1);
+                }
+            }
+        }
+
+        return dp[amount] > amount ? -1 : dp[amount];
+    }
+}
diff --git a/find-minimum-in-rotated-sorted-array/kimjunyoung90.java b/find-minimum-in-rotated-sorted-array/kimjunyoung90.java
new file mode 100644
index 0000000000..651d4ff55d
--- /dev/null
+++ b/find-minimum-in-rotated-sorted-array/kimjunyoung90.java
@@ -0,0 +1,18 @@
+// 요구사항 : 이진 탐색 이용
+class Solution {
+    public int findMin(int[] nums) {
+        int left = 0;
+        int right = nums.length - 1;
+        while(left < right) {
+            int mid = (left + right) / 2;
+            //중앙 값이 오른쪽 값보다 크다. = 최소값이 오른쪽 구간에 있음
+            if(nums[mid] > nums[right]) {
+                left = mid + 1;
+            } else {
+                right = mid;
+            }
+        }
+
+        return nums[left];
+    }
+}
diff --git a/word-search/kimjunyoung90.java b/word-search/kimjunyoung90.java
new file mode 100644
index 0000000000..606459190f
--- /dev/null
+++ b/word-search/kimjunyoung90.java
@@ -0,0 +1,42 @@
+class Solution {
+    public boolean exist(char[][] board, String word) {
+
+        int rows = board.length;
+        int columns = board[0].length;
+        boolean[][] visited = new boolean[rows][columns];
+        for (int i = 0; i < rows; i++) {
+            for (int j = 0; j < columns; j++) {
+                if (dfs(board, word, i, j, 0, visited)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    private boolean dfs(char[][] board, String word, int row, int col, int idx, boolean[][] visited) {
+        //예외 처리 1
+        if (idx == word.length()) return true;
+
+        //예외 처리 2
+        if (row < 0 || col < 0 || row >= board.length || col >= board[0].length) return false;
+
+        //예외 처리 3
+        if (visited[row][col]) return false;
+
+        //1. 글자 체크
+        if (board[row][col] != word.charAt(idx)) return false;
+
+        //방문 처리
+        visited[row][col] = true;
+
+        //상, 하, 좌, 우 찾기
+        boolean found = dfs(board, word, row + 1, col, idx + 1, visited)
+                || dfs(board, word, row - 1, col, idx + 1, visited)
+                || dfs(board, word, row, col + 1, idx + 1, visited)
+                || dfs(board, word, row, col - 1, idx + 1, visited);
+
+        visited[row][col] = false;
+        return found;
+    }
+}