[20250723] BOJ / G4 / 배수 공사 / 이강현

lkhyun/202507/23 BOJ G4 배수공사.md

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+```java
+import java.util.*;
+import java.io.*;
+
+public class Main{
+    static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    static StringTokenizer st;
+    static int N,X;
+    static int[] pipeLen;
+    static int[] pipeCnt;
+    static int[] dp; // dp[i] = 길이 i를 만드는 방법의 수
+
+    public static void main(String[] args) throws Exception {
+        st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        X = Integer.parseInt(st.nextToken());
+
+        pipeLen = new int[N];
+        pipeCnt = new int[N];
+        dp = new int[X+1];
+
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            pipeLen[i] = Integer.parseInt(st.nextToken());
+            pipeCnt[i] = Integer.parseInt(st.nextToken()); 
+        }
+
+        dp[0] = 1;
+        for (int i = 0; i < N; i++) { //모든 파이프에 대하여
+            for (int j = X; j >= 0; j--) { //길이를 고려
+                for (int k = 1; k <= pipeCnt[i]; k++) {
+                    if(j - pipeLen[i]*k >= 0){
+                        dp[j] += dp[j-pipeLen[i]*k];
+                    }
+                }
+            }
+        }
+        bw.write(dp[X]+"");
+        bw.close();
+    }
+}
+```