add: PCCP 기출문제 2번 - 석유 시추

Author: junest66

programmers/pccp-problem1/OilDrilling.java

@@ -0,0 +1,66 @@
+import java.util.*;
+import java.util.stream.*;
+
+class Solution {
+    static List<Integer> list = new ArrayList<>();
+    static int current = 0;
+    static int[][] visited;
+    static int[][] board;
+    static int[][] d = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
+    static int n, m;
+
+    public int solution(int[][] land) {
+        board = land;
+        n = land.length;
+        m = land[0].length;
+        visited = new int[n][m];
+        for(int i = 0; i < n; i++) {
+            Arrays.fill(visited[i], -1);
+        }
+        for(int i = 0; i < n; i++) {
+            for(int j = 0; j < m; j++) {
+                if(land[i][j] == 1 && visited[i][j] == -1) {
+                    list.add(bfs(i, j));
+                    current++;
+                }
+            }
+        }
+
+        int answer = 0;
+        for(int j = 0; j < m; j++) {
+            final int row = j;
+            int value = IntStream.range(0, n)
+                    .map(i -> visited[i][row])
+                    .filter(index -> index != -1)
+                    .distinct()
+                    .map(a -> list.get(a))
+                    .sum();
+            answer = Math.max(answer, value);
+        }
+        return answer;
+    }
+
+    int bfs(int i, int j) {
+        int sum = 0;
+        Deque<int[]> que= new ArrayDeque<>();
+        que.offer(new int[]{i, j});
+        visited[i][j] = current;
+        while(!que.isEmpty()) {
+            sum++;
+            int[] cur = que.poll();
+
+            for(int[] next : d) {
+                int ny = next[0] + cur[0];
+                int nx = next[1] + cur[1];
+                if(!isValidRange(ny, nx) || visited[ny][nx] != -1 || board[ny][nx] != 1) continue;
+                visited[ny][nx] = current;
+                que.offer(new int[]{ny, nx});
+            }
+        }
+        return sum;
+    }
+
+    private boolean isValidRange(int r, int c) {
+        return r >= 0 && c >= 0 && r < n && c < m;
+    }
+}