From 1a9867ec1428a9c17774c8211084f0a3d347f588 Mon Sep 17 00:00:00 2001
From: BangDori <qudwns8865@naver.com>
Date: Sun, 15 Dec 2024 00:44:53 +0900
Subject: [PATCH 1/2] Shortest Bridge

---
 bangdori/Shortest Bridge.js | 94 +++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 bangdori/Shortest Bridge.js

diff --git a/bangdori/Shortest Bridge.js b/bangdori/Shortest Bridge.js
new file mode 100644
index 0000000..62f622a
--- /dev/null
+++ b/bangdori/Shortest Bridge.js	
@@ -0,0 +1,94 @@
+const WATER = 0;
+const ISLAND = 1;
+const ISLAND2 = 2;
+const DIRS = [
+  [-1, 0],
+  [1, 0],
+  [0, -1],
+  [0, 1],
+];
+
+/**
+ * @param {number[][]} grid
+ * @return {number}
+ */
+var shortestBridge = function (grid) {
+  const rows = grid.length;
+  const cols = grid[0].length;
+
+  let queue = [];
+
+  const exploreIslandDFS = (row, col) => {
+    if (grid[row][col] === ISLAND2) return;
+
+    grid[row][col] = ISLAND2;
+    queue.push([row, col]);
+
+    for (let [dx, dy] of DIRS) {
+      const nextRow = row + dx;
+      const nextCol = col + dy;
+
+      if (
+        nextRow >= 0 &&
+        nextRow < rows &&
+        nextCol >= 0 &&
+        nextCol < cols &&
+        grid[nextRow][nextCol] === ISLAND
+      ) {
+        exploreIslandDFS(nextRow, nextCol);
+      }
+    }
+  };
+
+  const connectIslandBFS = () => {
+    /**
+     * 이동 거리를 나타내는 변수
+     * ISLAND와 차이를 두기 위해 음수값으로 적용
+     */
+    let distance = -1;
+    let currentQueue = queue;
+
+    while (currentQueue.length > 0) {
+      queue = [];
+
+      for (const [row, col] of currentQueue) {
+        for (const [dx, dy] of DIRS) {
+          const nextRow = row + dx;
+          const nextCol = col + dy;
+
+          if (
+            nextRow >= 0 &&
+            nextRow < rows &&
+            nextCol >= 0 &&
+            nextCol < cols
+          ) {
+            if (grid[nextRow][nextCol] === WATER) {
+              queue.push([nextRow, nextCol]);
+              grid[nextRow][nextCol] = distance;
+            }
+
+            if (grid[nextRow][nextCol] === ISLAND) {
+              return (distance + 1) * -1;
+            }
+          }
+        }
+      }
+
+      distance -= 1;
+      currentQueue = queue;
+    }
+
+    return 1;
+  };
+
+  for (let r = 0; r < rows; r++) {
+    for (let c = 0; c < cols; c++) {
+      if (grid[r][c] === WATER) continue;
+
+      exploreIslandDFS(r, c);
+      return connectIslandBFS();
+    }
+  }
+
+  return -1; // Error
+};

From e7cdea32846293d5baf47b3edcf8baaab3ee83d6 Mon Sep 17 00:00:00 2001
From: BangDori <qudwns8865@naver.com>
Date: Mon, 16 Dec 2024 00:22:53 +0900
Subject: [PATCH 2/2] =?UTF-8?q?=EC=A4=91=EB=B3=B5=20=EB=A9=94=EC=84=9C?=
 =?UTF-8?q?=EB=93=9C=20=EB=B6=84=EB=A6=AC?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 bangdori/Shortest Bridge.js | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/bangdori/Shortest Bridge.js b/bangdori/Shortest Bridge.js
index 62f622a..49e4cde 100644
--- a/bangdori/Shortest Bridge.js	
+++ b/bangdori/Shortest Bridge.js	
@@ -29,10 +29,7 @@ var shortestBridge = function (grid) {
       const nextCol = col + dy;
 
       if (
-        nextRow >= 0 &&
-        nextRow < rows &&
-        nextCol >= 0 &&
-        nextCol < cols &&
+        isValidCoords(nextRow, nextCol) &&
         grid[nextRow][nextCol] === ISLAND
       ) {
         exploreIslandDFS(nextRow, nextCol);
@@ -56,12 +53,7 @@ var shortestBridge = function (grid) {
           const nextRow = row + dx;
           const nextCol = col + dy;
 
-          if (
-            nextRow >= 0 &&
-            nextRow < rows &&
-            nextCol >= 0 &&
-            nextCol < cols
-          ) {
+          if (isValidCoords(nextRow, nextCol)) {
             if (grid[nextRow][nextCol] === WATER) {
               queue.push([nextRow, nextCol]);
               grid[nextRow][nextCol] = distance;
@@ -81,6 +73,9 @@ var shortestBridge = function (grid) {
     return 1;
   };
 
+  const isValidCoords = (row, col) =>
+    row >= 0 && row < rows && col >= 0 && col < cols;
+
   for (let r = 0; r < rows; r++) {
     for (let c = 0; c < cols; c++) {
       if (grid[r][c] === WATER) continue;