[20250210] BOJ / 플래3 / 도형 / 권혁준

Author: oncsr

khj20006/202502/11 BOJ P3 도형.md

@@ -0,0 +1,75 @@
+```java
+
+import java.util.*;
+import java.io.*;
+
+
+class Main {
+	
+	// IO field
+	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+	static StringTokenizer st;
+
+	static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+	static int nextInt() {return Integer.parseInt(st.nextToken());}
+	static long nextLong() {return Long.parseLong(st.nextToken());}
+	static void bwEnd() throws Exception {bw.flush();bw.close();}
+	
+	// Additional field
+	
+	static int[] A;
+	static long[][] dp;
+	static long[][] sum;
+	static int N, K;
+	
+	public static void main(String[] args) throws Exception {
+		
+		ready();
+		solve();
+	
+		bwEnd();
+	}
+	
+	static void ready() throws Exception{
+
+		N = Integer.parseInt(br.readLine());
+		A = new int[N];
+		nextLine();
+		for(int i=0;i<N;i++) A[i] = nextInt();
+		K = Integer.parseInt(br.readLine());
+		dp = new long[500001][K+1];
+		sum = new long[500001][K+1];
+		
+	}
+	
+	static void solve() throws Exception{
+
+		Arrays.sort(A);
+		dp[A[0]][1] = 1;
+		sum[A[0]][1] = 1;
+		for(int i=1;i<N;i++) {
+			for(int s=500000;s>2*A[i];s--) {
+				for(int k=K;k>2;k--) {
+					dp[s][k] += sum[s-A[i]][k-1];
+				}
+			}
+			for(int s=500000;s>A[i];s--) {
+				for(int k=K;k>1;k--) {
+					sum[s][k] += sum[s-A[i]][k-1];
+				}
+			}
+			for(int s=500000;s>A[i];s--) if(dp[s-A[i]][1] != 0) dp[s][2] += dp[s-A[i]][1];
+			dp[A[i]][1]++;
+			sum[A[i]][1]++;
+		}
+		
+		long ans = 0;
+		for(int i=1;i<=500000;i++) ans += dp[i][K];
+		bw.write(ans+"\n");
+		
+	}
+	
+}
+
+```