v.2.0.2 doBacktracking return Matrix-String

apps/n-dame-problem/src/n-dame-problem.controller.ts

@@ -38,8 +38,20 @@ export class NDameProblemController {
     @Query('starting-position', new DefaultValuePipe(-1), ParseIntPipe)
     startingPosition: number,
   ) {
-    return this.nDameProblemService
-      .doBacktracking(startingPosition, modelSize)
-      .map((row) => row.map((col) => (col ? 'X' : '.')));
+    const backtrackMatrix: boolean[][] =
+      this.nDameProblemService.doBacktracking(startingPosition, modelSize);
+
+    const resultMatrix = backtrackMatrix.map((row: boolean[]) =>
+      row.map((b: boolean) => (b ? ' X' : ' .')),
+    );
+    const verticalLine = ' '.concat(''.padStart(modelSize * 2, '_'), ' ');
+    const resultMatrixStr = '\n|'.concat(
+      resultMatrix.map((row) => row.join('').concat('|\n')).join('|'),
+    );
+
+    return verticalLine.concat(
+      resultMatrixStr,
+      verticalLine.replaceAll('_', '~'),
+    );
   }
 }