[20250912] BOJ / G4 / RGB거리 2 / 한종욱

Author: Ukj0ng

Ukj0ng/202509/12 BOJ G4 RGB거리 2.md

@@ -0,0 +1,70 @@
+```
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    private static final BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+    private static final BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+    private static final int INF = 1000010;
+    private static int[][] cost, dp;
+    private static int N;
+
+    public static void main(String[] args) throws IOException {
+        init();
+
+        int answer = Integer.MAX_VALUE;
+        for (int i = 0; i < 3; i++) {
+            DP(i);
+
+            for (int j = 0; j < 3; j++) {
+                answer = Math.min(answer, dp[N-1][j]);
+            }
+        }
+
+        bw.write(answer + "\n");
+        bw.flush();
+        bw.close();
+        br.close();
+
+    }
+
+    private static void init() throws IOException {
+        N = Integer.parseInt(br.readLine());
+
+        cost = new int[N][3];
+        dp = new int[N][3];
+
+        for (int i = 0; i < N; i++) {
+            StringTokenizer st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < 3; j++) {
+                cost[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+    }
+
+    private static void DP(int start) {
+        for (int i = 0; i < N; i++) Arrays.fill(dp[i], INF);
+
+        dp[0][start] = cost[0][start];
+
+        for (int i = 1; i < N-1; i++) {
+            dp[i][0] = cost[i][0] + Math.min(dp[i-1][1], dp[i-1][2]);
+            dp[i][1] = cost[i][1] + Math.min(dp[i-1][0], dp[i-1][2]);
+            dp[i][2] = cost[i][2] + Math.min(dp[i-1][0], dp[i-1][1]);
+        }
+
+        for (int i = 0; i < 3; i++) {
+            if (i == start) continue;
+
+            int min = INF;
+
+            for (int j = 0; j < 3; j++) {
+                if (i == j) continue;
+                min = Math.min(min, dp[N-2][j]);
+            }
+
+            dp[N-1][i] = cost[N-1][i] + min;
+        }
+    }
+}
+```