diff --git a/code_study/Baekjoon/java/_10775.java b/code_study/Baekjoon/java/_10775.java
new file mode 100644
index 0000000..ad57a13
--- /dev/null
+++ b/code_study/Baekjoon/java/_10775.java
@@ -0,0 +1,43 @@
+import java.util.*;
+
+public class _10775 {
+    static int[] parents;
+    static int ans = 0;
+
+    static int find(int x) {
+        if(parents[x] != x) return parents[x] = find(parents[x]);
+        return parents[x]; 
+    }
+
+    static void union(int x, int y) {
+        x = find(x);
+        y = find(y);
+
+        if(x > y) {
+            int temp = x;
+            x = y;
+            y = temp;
+        }
+
+        parents[y] = x;
+    }
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int G = sc.nextInt(), P = sc.nextInt();
+        parents = new int[G+1];
+        for(int i=1; i<=G; i++) parents[i] = i;
+
+        for(int i=0; i<P; i++) {
+            int gi = sc.nextInt();
+            gi = find(gi);
+            
+            if(gi == 0) break;
+
+            union(gi, gi-1);
+            ans++;
+        }
+        System.out.println(ans);
+
+        sc.close();
+    }    
+}
diff --git a/code_study/Baekjoon/java/_10830.java b/code_study/Baekjoon/java/_10830.java
new file mode 100644
index 0000000..316af0e
--- /dev/null
+++ b/code_study/Baekjoon/java/_10830.java
@@ -0,0 +1,63 @@
+import java.util.*;
+
+public class _10830 {
+    static int MOD = 1000;
+
+    static void print_mat(int[][] M, int N) {
+        for (int[] row : M) {
+            for(int i=0; i<N; i++) System.out.printf("%d ",row[i]);
+            System.out.println();
+        }
+    }
+
+    static int[][] mul_mat(int[][] m1, int[][] m2, int N) {
+        int[][] result = new int[N][N];
+
+        for(int i=0; i<N; i++) {
+            for(int j=0; j<N; j++) {
+                for(int k=0; k<N; k++) {
+                    result[i][j] += m1[i][k]*m2[k][j];
+                }
+                result[i][j] %= MOD;
+            }
+        }
+
+        return result;
+    }
+
+    static int[][] power_mat(int[][] A, long B, int N) {
+        int[][] result = new int[N][N];
+        
+        if(B==1) {
+            for(int i=0; i<N; i++) {
+                for(int j=0; j<N; j++) {
+                    result[i][j] = A[i][j]%MOD;
+                }
+            }
+            return result;
+        }
+
+        int[][] temp = power_mat(A, B/2, N);
+
+        if(B%2 == 0) return mul_mat(temp, temp, N);
+
+        return mul_mat(mul_mat(temp, temp, N), A, N);
+    }
+
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        int N = sc.nextInt();
+        long B = sc.nextLong();
+        
+        int[][] A = new int[N][N];
+        for(int i=0; i<N; i++) {
+            for(int j=0; j<N; j++) {
+                A[i][j] = sc.nextInt();
+            }
+        }
+        sc.close();
+
+        int[][] result = power_mat(A, B, N);
+        print_mat(result, N);
+    }
+}