Merge pull request #672 from AlgorithmWithGod/lkhyun

[20250816] BOJ / G2 / 소가 길을 건너간 이유 7 / 이강현

Author: ShinHeeEul

lkhyun/202508/16 BOJ G2 소가 길을 건너간 이유 7.md

@@ -0,0 +1,72 @@
+```java
+import java.io.*;
+import java.util.*;
+
+public class Main {
+    static int N,T;
+    static int[][] farm;
+    static long[][][] dist;
+    static int[] di = {0,0,-1,1};
+    static int[] dj = {-1,1,0,0};
+    static long ans;
+
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        T = Integer.parseInt(st.nextToken());
+        farm = new int[N][N];
+
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            for (int j = 0; j < N; j++) {
+                farm[i][j] = Integer.parseInt(st.nextToken());
+            }
+        }
+
+        dijkstra();
+        bw.write(ans+"");
+        bw.close();
+    }
+
+    static void dijkstra(){
+        dist = new long[N][N][3];
+        for (int i = 0; i < N; i++) {
+            for (int j = 0; j < N; j++) {
+                Arrays.fill(dist[i][j],Long.MAX_VALUE);
+            }
+        }
+        dist[0][0][0] = 0;
+        PriorityQueue<long[]> pq = new PriorityQueue<>((a,b) -> Long.compare(a[2],b[2]));
+        pq.offer(new long[]{0,0,0,0}); // a,b,c,d : [a][b]까지 가는데 c만큼 걸리고 길 건넌 횟수는 d이다.
+
+        while(!pq.isEmpty()){
+            long[] cur = pq.poll();
+
+            if(dist[(int)cur[0]][(int)cur[1]][(int)cur[3]] < cur[2]) continue;
+    
+            for (int k = 0; k < 4; k++) {
+                int newi = (int)(cur[0] + di[k]);
+                int newj = (int)(cur[1] + dj[k]);
+                if(check(newi,newj)){
+                    long newDist = cur[2] + T;
+                    int newCross = (int)(cur[3]+1) % 3;
+                    if(newCross == 0){
+                        newDist += farm[newi][newj];
+                    }
+                    if(newDist < dist[newi][newj][newCross]){
+                        dist[newi][newj][newCross] = newDist;
+                        pq.offer(new long[]{newi,newj,newDist,newCross});
+                    }
+                }
+            }
+        }
+        ans = Math.min(dist[N-1][N-1][0],Math.min(dist[N-1][N-1][1], dist[N-1][N-1][2]));
+    }
+    static boolean check(long a, long b){
+        if(a<0 || a>=N || b<0 || b>=N) return false;
+        return true;
+    }
+}
+```