[20250629] BOJ / G4 / RGB거리 2 / 이강현

Author: lkhyun

lkhyun/202506/29 BOJ G4 RGB거리 2.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;
+    static int[][] cost;
+    static int[][] dp;
+    
+    public static void main(String[] args) throws Exception{
+      N = Integer.parseInt(br.readLine());
+      cost = new int[N+1][3];
+      
+      for(int i=1; i<=N;i++){
+        st = new StringTokenizer(br.readLine());
+        cost[i][0] = Integer.parseInt(st.nextToken());
+        cost[i][1] = Integer.parseInt(st.nextToken());
+        cost[i][2] = Integer.parseInt(st.nextToken());
+      }
+      
+      int min = Integer.MAX_VALUE;
+      for(int firstColor=0; firstColor<3; firstColor++){
+        dp = new int[N+1][3];
+        dp[1][firstColor] = cost[1][firstColor];
+        dp[1][(firstColor+1)%3] = 10000000;
+        dp[1][(firstColor+2)%3] = 10000000;
+        
+        for(int i=2;i<N;i++){
+          for(int j = 0;j<3;j++){
+            dp[i][j] = Math.min(dp[i-1][(j+1)%3] + cost[i][j], dp[i-1][(j+2)%3] + cost[i][j]);
+          }
+        }
+        dp[N][(firstColor+1)%3] = Math.min(dp[N-1][firstColor]+cost[N][(firstColor+1)%3], dp[N-1][(firstColor+2)%3]+cost[N][(firstColor+1)%3]);
+        dp[N][(firstColor+2)%3] = Math.min(dp[N-1][firstColor]+cost[N][(firstColor+2)%3], dp[N-1][(firstColor+1)%3]+cost[N][(firstColor+2)%3]);
+
+        min = Math.min(min, dp[N][(firstColor+1)%3]);
+        min = Math.min(min, dp[N][(firstColor+2)%3]);
+      }
+      bw.write(min+"");
+      bw.close();
+  }
+}
+```