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| 1 | +```java |
| 2 | +import java.io.BufferedReader; |
| 3 | +import java.io.IOException; |
| 4 | +import java.io.InputStreamReader; |
| 5 | + |
| 6 | +public class Main { |
| 7 | + private static BufferedReader br; |
| 8 | + |
| 9 | + public static void main(String[] args) throws IOException { |
| 10 | + br = new BufferedReader(new InputStreamReader(System.in)); |
| 11 | + String[] temp = br.readLine().split(" "); |
| 12 | + int n = Integer.parseInt(temp[0]); |
| 13 | + int m = Integer.parseInt(temp[1]); |
| 14 | + |
| 15 | + int[][] map = new int[n][m]; |
| 16 | + for (int i = 0; i < n; i++) { |
| 17 | + temp = br.readLine().split(" "); |
| 18 | + for (int j = 0; j < m; j++) { |
| 19 | + map[i][j] = Integer.parseInt(temp[j]); |
| 20 | + } |
| 21 | + } |
| 22 | + |
| 23 | + int[][][] dp = new int[n][m + 2][3]; |
| 24 | + int INF = Integer.MAX_VALUE; |
| 25 | + |
| 26 | + for (int c = 1; c <= m; c++) { |
| 27 | + for (int d = 0; d < 3; d++) { |
| 28 | + dp[0][c][d] = map[0][c - 1]; // map은 0-based |
| 29 | + } |
| 30 | + } |
| 31 | + for (int r = 1; r < n; r++) { |
| 32 | + for (int c = 1; c <= m; c++) { |
| 33 | + for (int dc : new int[] { -1, 0, 1 }) { |
| 34 | + int dp2index = dc + 1; |
| 35 | + int targetC = c + dc; |
| 36 | + if (targetC < 1 || targetC > m) { |
| 37 | + dp[r][c][dp2index] = INF; |
| 38 | + continue; |
| 39 | + } |
| 40 | + |
| 41 | + int minPrev = INF; |
| 42 | + for (int prevD = 0; prevD < 3; prevD++) { |
| 43 | + if (prevD == dp2index) continue; // 같은 방향 연속 이동 금지 |
| 44 | + minPrev = Math.min(minPrev, dp[r - 1][targetC][prevD]); |
| 45 | + } |
| 46 | + if (minPrev == INF) |
| 47 | + dp[r][c][dp2index] = INF; |
| 48 | + else |
| 49 | + dp[r][c][dp2index] = minPrev + map[r][c - 1]; |
| 50 | + } |
| 51 | + } |
| 52 | + } |
| 53 | + |
| 54 | + int answer = INF; |
| 55 | + for (int c = 1; c <= m; c++) { |
| 56 | + for (int d = 0; d < 3; d++) { |
| 57 | + answer = Math.min(answer, dp[n - 1][c][d]); |
| 58 | + } |
| 59 | + } |
| 60 | + System.out.println(answer); |
| 61 | + } |
| 62 | +} |
| 63 | +``` |
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