Added 1 JS solution for problem 130

Author: imaginate

javascript/130-Surrounded-Regions.js

@@ -0,0 +1,70 @@
+//////////////////////////////////////////////////////////////////////////////
+// Depth First Search (DFS)
+// Time: O(m*n)
+// Space: O(m*n)
+// You can implement either Depth First Search (DFS) or Breadth First Search
+// (BFS). The only noticeable impact is the performance cost of the BFS queue
+// is higher than the DFS call stack.
+//////////////////////////////////////////////////////////////////////////////
+
+/**
+ * @param {character[][]} board
+ * @return {void} Do not return anything, modify board in-place instead.
+ */
+function solve(board) {
+    
+    const rowLen = board.length;
+    const colLen = board[0].length;
+    const lastRow = rowLen - 1;
+    const lastCol = colLen - 1;
+    
+    for (let r = 0; r < rowLen; ++r) {
+        markSeen(r, 0);
+        markSeen(r, lastCol);
+    }
+    for (let c = 1; c < lastCol; ++c) {
+        markSeen(0, c);
+        markSeen(lastRow, c);
+    }
+    
+    for (let r = 0; r < rowLen; ++r) {
+        for (let c = 0; c < colLen; ++c) {
+            switch (board[r][c]) {
+                case 'O':
+                    board[r][c] = 'X';
+                    break;
+                case 'A':
+                    board[r][c] = 'O';
+                    break;
+            }
+        }
+    }
+    
+    /**
+     * @param {number} r
+     * @param {number} c
+     * @return {void}
+     */
+    function markSeen(r, c) {
+        
+        if (!inBounds(r, c) || board[r][c] !== 'O') {
+            return;
+        }
+        
+        board[r][c] = 'A';
+        
+        markSeen(r - 1, c);
+        markSeen(r + 1, c);
+        markSeen(r, c - 1);
+        markSeen(r, c + 1);
+    }
+    
+    /**
+     * @param {number} r
+     * @param {number} c
+     * @return {boolean}
+     */
+    function inBounds(r, c) {
+        return r >= 0 && c >= 0 && r < rowLen && c < colLen;
+    }
+}