diff --git "a/ShinHeeEul/202502/04 BOJ P4 \354\210\230\354\227\264\352\263\274 \354\277\274\353\246\254 21.md" "b/ShinHeeEul/202502/04 BOJ P4 \354\210\230\354\227\264\352\263\274 \354\277\274\353\246\254 21.md"
new file mode 100644
index 00000000..4384d1f6
--- /dev/null
+++ "b/ShinHeeEul/202502/04 BOJ P4 \354\210\230\354\227\264\352\263\274 \354\277\274\353\246\254 21.md"	
@@ -0,0 +1,114 @@
+```java
+import java.util.*;
+import java.io.*;
+
+public class Main {
+	
+	static long[] segments;
+	static long[] lazy;
+	static int size;
+	static int N;
+	
+	public static void main(String[] args) throws Exception {
+		N = read();
+		
+		size = 1;
+		while(size < N) size <<= 1;
+		
+		segments = new long[(size << 1) + 1];
+		lazy = new long[(size << 1) + 1];
+		
+		for(int i = size + 1; i < (size + N + 1); i++) {
+			segments[i] = read();
+		}
+		
+		int segmentSize = size << 1;
+		
+		while(segmentSize > 1) {
+			segments[segmentSize >> 1] = segments[segmentSize] + segments[segmentSize - 1];
+			segmentSize -= 2;
+		}
+		
+		int M = read();
+		StringBuilder sb = new StringBuilder();
+		while(M --> 0) {
+			int a = read();
+			if(a == 1) {
+				int i = read();
+				int j = read();
+				int k = read();
+				updateLazy(i, j, 2, 1, size, k);
+			} else {
+				int x = read();
+				sb.append(query(x,x,2,1,size)).append("\n");
+			}
+		}
+		System.out.println(sb);
+	}
+	
+	public static void update(int node, int start, int end) {
+		// 현재 값 노드에 더하고?
+		segments[node] += lazy[node] * (int) (end - start + 1);
+		
+		// 밑으로 전파 시키고
+		if(node > size) {
+			lazy[node] = 0;
+			return;
+		}
+
+		int index = node << 1;
+		lazy[index] += lazy[node];
+		lazy[index-1] += lazy[node];
+
+		lazy[node] = 0;
+	}
+	
+	public static void updateLazy(int left, int right, int node, int start, int end, int val) {
+		if(end < left || start > right) return;
+		
+		if(left <= start && end <= right) {
+			lazy[node] += val;
+			update(node, start, end);
+			return;
+		}
+		
+		int mid = (start + end) >> 1;
+		
+		updateLazy(left, right, (node << 1) - 1, start, mid, val);
+		updateLazy(left, right, node << 1, mid + 1, end , val);
+		
+	}
+	
+	public static long query(int left, int right, int node, int start, int end) {
+		
+		if(lazy[node] != 0) {
+			update(node, start, end);
+		}
+		
+		if(end < left || start > right) return 0L;
+		
+		if(left <= start && end <= right) {
+			return segments[node];
+		}
+		
+		int mid = (start + end) >> 1;
+		return query(left, right, (node << 1) - 1, start, mid) + query(left, right, (node << 1), mid + 1, end);
+	}
+	
+	 private static int read() throws Exception {
+	        int d, o;
+	        boolean negative = false;
+	        d = System.in.read();
+
+	        if (d == '-') {
+	            negative = true;
+	            d = System.in.read();
+	        }
+	        o = d & 15;
+	        while ((d = System.in.read()) > 32)
+	            o = (o << 3) + (o << 1) + (d & 15);
+
+	        return negative? -o:o;
+	    }
+}
+```