[leet] surrounded region (mid)

Author: hyeonbinHur

허현빈/7주차/260209.js

@@ -0,0 +1,60 @@
+var solve = function (board) {
+  if (!board.length) return;
+
+  const rows = board.length;
+  const cols = board[0].length;
+  const visited = Array.from({ length: rows }, () => Array(cols).fill(false));
+  const dir = [
+    [1, 0],
+    [-1, 0],
+    [0, 1],
+    [0, -1],
+  ];
+
+  const bfs = (r, c) => {
+    const queue = [[r, c]];
+    const path = [[r, c]];
+    visited[r][c] = true;
+    let isSurrounded = true;
+
+    while (queue.length) {
+      const [curY, curX] = queue.shift();
+
+      if (curY === 0 || curY === rows - 1 || curX === 0 || curX === cols - 1) {
+        isSurrounded = false;
+      }
+
+      for (let i = 0; i < dir.length; i++) {
+        const ny = curY + dir[i][0];
+        const nx = curX + dir[i][1];
+
+        if (
+          ny >= 0 &&
+          ny < rows &&
+          nx >= 0 &&
+          nx < cols &&
+          board[ny][nx] === "O" &&
+          !visited[ny][nx]
+        ) {
+          visited[ny][nx] = true;
+          queue.push([ny, nx]);
+          path.push([ny, nx]);
+        }
+      }
+    }
+
+    if (isSurrounded) {
+      for (const [y, x] of path) {
+        board[y][x] = "X";
+      }
+    }
+  };
+
+  for (let i = 0; i < rows; i++) {
+    for (let j = 0; j < cols; j++) {
+      if (board[i][j] === "O" && !visited[i][j]) {
+        bfs(i, j);
+      }
+    }
+  }
+};