v.2.0.0 NDameBacktracker implementation

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

@@ -0,0 +1,21 @@
+import { ABacktracker } from '@app/backtracking-lib/abstract-backtracker';
+import { NDameModel } from './n-dame-model';
+
+export class NDameBacktracker extends ABacktracker {
+  private _model: NDameModel;
+
+  constructor(private readonly modelSize: number) {
+    super();
+    this._model = new NDameModel(modelSize);
+  }
+
+  get model() {
+    return this._model;
+  }
+
+  doBacktrack = (): boolean[][] => {
+    const bSolution = this.findSolution(this._model);
+
+    return this.model.matrix;
+  };
+}

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

@@ -1,22 +0,0 @@
-import { NDameModel } from './n-dame-model';
-
-export class NDameBacktracking {
-  private model: NDameModel;
-
-  constructor(private readonly modelSize: number) {
-    this.model = new NDameModel(modelSize);
-  }
-
-  options = (): Array<number> => {
-    // const optionsArray = Array.from(
-    //   { length: this.modelSize },
-    //   (value, index) => index,
-    // );
-    // wir können nur 1 Dame pro Feld platzieren !!!
-    return [1];
-  };
-
-  solved = (): boolean => {
-    return this.model.solved();
-  };
-}

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

@@ -1,4 +1,4 @@
-import { IBacktracking } from '@app/backtracking-lib/backtracking.interface';
+import { IBacktrackingModel } from '@app/backtracking-lib/backtracking-model.interface';
 import { MatrixPosition } from '@app/backtracking-lib/matrix-position';
 import { Logger } from '@nestjs/common';
 
@@ -7,29 +7,33 @@ enum EDiagonal {
   NO_SW = -1,
 }
 
-export class NDameModel implements IBacktracking {
+export class NDameModel implements IBacktrackingModel {
   private readonly logger = new Logger(this.constructor.name);
 
   private nDamesMatrix: boolean[][] = [];
   // Wert initial setzen, damit nextPosition beim ersten Schritt richtig platziert wird
   private modelPosition: MatrixPosition = new MatrixPosition(
     -1,
-    this.modelSize - 1,
+    this._modelSize - 1,
   );
 
-  constructor(private readonly modelSize: number) {
+  constructor(private readonly _modelSize: number) {
     this.initNDameField();
   }
 
   private initNDameField() {
-    for (var zeile = 0; zeile < this.modelSize; zeile++) {
+    for (var zeile = 0; zeile < this._modelSize; zeile++) {
       this.nDamesMatrix[zeile] = [];
-      for (var spalte = 0; spalte < this.modelSize; spalte++) {
+      for (var spalte = 0; spalte < this._modelSize; spalte++) {
         this.nDamesMatrix[zeile].push(false);
       }
     }
   }
 
+  public get modelSize() {
+    return this._modelSize;
+  }
+
   public get matrix(): boolean[][] {
     return this.nDamesMatrix;
   }
@@ -43,43 +47,58 @@ export class NDameModel implements IBacktracking {
 
   // sind alle N Damen auf dem Feld platziert ?
   public solved = (): boolean => {
-    return this.dames == this.modelSize;
+    return this.dames == this._modelSize;
   };
 
-  options = (): Array<number> => {
-    // wir können nur 1 Dame pro Feld platzieren !!!
-    return [1];
+  hasNext = (): boolean => {
+    if (
+      // wenn das Maximum erreicht haben ist Schluss
+      this.modelPosition.row === this.modelSize - 1 &&
+      this.modelPosition.col === this.modelSize - 1
+    )
+      return false;
 
-    // const optionsArray = Array.from(
-    //   { length: this.modelSize },
-    //   (value, index) => index,
-    // );
+    return true;
   };
 
   nextPosition = () => {
     this.modelPosition.col++;
 
-    if (this.modelPosition.col == this.modelSize) {
+    if (this.modelPosition.col == this._modelSize) {
       this.modelPosition.row++;
       this.modelPosition.col = 0;
     }
 
-    if (this.modelPosition.row == this.modelSize)
+    if (this.modelPosition.row == this._modelSize)
       throw new Error(`model bounds crashed...\n${this.modelPosition}`);
 
     return this.modelPosition;
   };
 
+  nextPossiblePosition = (): boolean => {
+    try {
+      var np = this.nextPosition();
+      var isPossible = false;
+      while (!isPossible) {
+        isPossible = this.positionPossible();
+        if (isPossible) return isPossible;
+
+        this.nextPosition();
+      }
+    } catch (error) {
+      return null;
+    }
+  };
+
   private rowProhibited = (): boolean => {
     const damesRow = this.nDamesMatrix[this.modelPosition.row];
 
     // steht schon eine Dame in der selben Zeile ?
     const damesInRow = damesRow.reduce((acc, act) => (act ? ++acc : acc), 0);
 
-    if (damesInRow > 1)
-      this.logger.error(`row occupied: ${this.modelPosition}`);
+    if (damesInRow > 0) this.logger.warn(`row occupied: ${this.modelPosition}`);
 
-    return damesInRow > 1;
+    return damesInRow > 0;
   };
 
   private colProhibited = (): boolean => {
@@ -91,24 +110,19 @@ export class NDameModel implements IBacktracking {
     // steht schon eine Dame in der selben Spalte ?
     const damesInCol = damesCol.reduce((acc, act) => (act ? ++acc : acc), 0);
 
-    if (damesInCol > 1)
-      this.logger.error(`col occupied: ${this.modelPosition}`);
+    if (damesInCol > 0) this.logger.warn(`col occupied: ${this.modelPosition}`);
 
-    return damesInCol > 1;
+    return damesInCol > 0;
   };
 
   private damesInDiagonal = (diagDirection: EDiagonal) => {
-    this.logger.log(
-      `diaginal ${diagDirection == EDiagonal.NW_SO ? 'NW_SO' : 'NO_SW'}`,
-    );
-
     // const startPos = { ...this.modelPosition };
     const startPos = new MatrixPosition(
       this.modelPosition.row,
       this.modelPosition.col,
     );
     const colSearchEndPos =
-      diagDirection == EDiagonal.NW_SO ? 0 : this.modelSize - 1;
+      diagDirection == EDiagonal.NW_SO ? 0 : this._modelSize - 1;
 
     var found = false;
 
@@ -124,9 +138,9 @@ export class NDameModel implements IBacktracking {
     var diagPos = startPos;
     const diagCoords = [];
     const damesDiag = [];
-    const colExitPos = diagDirection == EDiagonal.NW_SO ? this.modelSize : -1;
+    const colExitPos = diagDirection == EDiagonal.NW_SO ? this._modelSize : -1;
     while (!diagReady) {
-      if (diagPos.row == this.modelSize || diagPos.col == colExitPos)
+      if (diagPos.row == this._modelSize || diagPos.col == colExitPos)
         diagReady = true;
       else {
         diagCoords.push(new MatrixPosition(diagPos.row, diagPos.col));
@@ -136,7 +150,6 @@ export class NDameModel implements IBacktracking {
       }
     }
 
-    this.logger.verbose(diagCoords.join());
     return damesDiag;
   };
 
@@ -156,12 +169,12 @@ export class NDameModel implements IBacktracking {
       0,
     );
 
-    if (damesInDiagonalNW_SO > 1)
-      this.logger.error(`diagNW_SO occupied: ${this.modelPosition}`);
-    if (damesInDiagonalNO_SW > 1)
-      this.logger.error(`diagNO_SW occupied: ${this.modelPosition}`);
+    if (damesInDiagonalNW_SO > 0)
+      this.logger.warn(`diagNW_SO occupied: ${this.modelPosition}`);
+    if (damesInDiagonalNO_SW > 0)
+      this.logger.warn(`diagNO_SW occupied: ${this.modelPosition}`);
 
-    return damesInDiagonalNW_SO > 1 || damesInDiagonalNO_SW > 1;
+    return damesInDiagonalNW_SO > 0 || damesInDiagonalNO_SW > 0;
   };
 
   // darf hier eine Dame stehen ?
@@ -179,14 +192,33 @@ export class NDameModel implements IBacktracking {
 
   // Dame auf das Feld platzieren
   applyPosition = (): MatrixPosition => {
-    this.logger.warn(`apply: ${JSON.stringify(this.modelPosition)}`);
+    this.logger.verbose(`apply: ${JSON.stringify(this.modelPosition)}`);
     this.nDamesMatrix[this.modelPosition.row][this.modelPosition.col] = true;
     return this.modelPosition;
   };
 
   // letzte Dame vom Feld nehmen
   discardPosition = (): MatrixPosition => {
-    this.nDamesMatrix[this.modelPosition.row][this.modelPosition.col] = false;
+    // 1. letzte Dame suchen
+    const lastDameFlatPos = this.nDamesMatrix.flat().lastIndexOf(true);
+    const lastDameRow = Math.floor(lastDameFlatPos / this.modelSize);
+    const lastDameCol = lastDameFlatPos % this.modelSize;
+
+    // 2. alle Damen kicken
+    // const resettedNDamesMatrix = this.nDamesMatrix.map((row) => {
+    //   const resettedRow = row.map(() => false);
+    //   return resettedRow;
+    // });
+    // 3. assign cleared Matrix
+    // this.nDamesMatrix = resettedNDamesMatrix;
+
+    // 3. Position auf Feld letzten Dame
+    this.modelPosition.row = lastDameRow;
+    this.modelPosition.col = lastDameCol;
+
+    // 4. Wert resetten
+    this.nDamesMatrix[lastDameRow][lastDameCol] = false;
+
     return this.modelPosition;
   };
 }

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

@@ -19,12 +19,25 @@ export class NDameProblemController {
   @Get('/model')
   getModel(
     @Query('field', new DefaultValuePipe(-1), ParseIntPipe) field: number,
+    @Query('model-size', new DefaultValuePipe(5), ParseIntPipe)
+    modelSize: number,
   ): boolean[][] {
-    return this.nDameProblemService.getModel(field);
+    // wenn field gesetzt, dann hat das Prio
+    return this.nDameProblemService.getModel(field, modelSize);
   }
 
   @Get('/backtracking')
   getBacktracking() {
     return this.nDameProblemService.getBacktracking();
   }
+
+  @Get('/do-backtracking')
+  doBacktracking(
+    @Query('model-size', new DefaultValuePipe(5), ParseIntPipe)
+    modelSize: number,
+  ) {
+    return this.nDameProblemService
+      .doBacktracking(modelSize)
+      .map((row) => row.map((col) => (col ? 'X' : 'O')));
+  }
 }

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

@@ -1,30 +1,48 @@
 import { Injectable, Logger } from '@nestjs/common';
 import { NDameModel } from './n-dame-model';
-import { NDameBacktracking } from './n-dame-backtracking';
+import { NDameBacktracker } from './n-dame-backtracker';
 
 @Injectable()
 export class NDameProblemService {
   private readonly logger = new Logger(this.constructor.name);
-  private readonly MODEL_SIZE = 5;
 
-  getBacktracking(): NDameBacktracking {
-    const backTracking = new NDameBacktracking(4);
+  doBacktracking(modelSize: number): boolean[][] {
+    const nDameBacktracker = new NDameBacktracker(modelSize);
 
-    this.logger.log(`${backTracking.options()}`);
-    backTracking.solved();
-
-    return backTracking;
+    return nDameBacktracker.doBacktrack();
   }
 
-  getModel(field: number): boolean[][] {
-    const model = new NDameModel(this.MODEL_SIZE);
-    const modelFieldCount = this.MODEL_SIZE * this.MODEL_SIZE;
+  getBacktracking(): NDameBacktracker {
+    const backTracker = new NDameBacktracker(5);
+
+    backTracker.model.solved();
+
+    for (var i = 0; i < 5; i++) {
+      backTracker.model.nextPosition();
+      backTracker.model.applyPosition();
+    }
+
+    backTracker.model.discardPosition();
+
+    backTracker.model.nextPosition();
+    backTracker.model.applyPosition();
+
+    return backTracker;
+  }
+
+  getModel(field: number, modelSize: number): boolean[][] {
+    const model = new NDameModel(modelSize);
+    const modelFieldCount = model.modelSize * model.modelSize;
     const rndFields = [];
 
     // geben wir keine FeldNr. an, dann die Zufallsreihe
     if (field === -1)
-      for (var i = 0; i < this.MODEL_SIZE; i++)
-        rndFields.push(Math.floor(Math.random() * modelFieldCount));
+      for (var i = 0; i < model.modelSize; i++) {
+        var rndNr = Math.floor(Math.random() * modelFieldCount);
+        while (rndFields.includes(rndNr))
+          rndNr = Math.floor(Math.random() * modelFieldCount);
+        rndFields.push(rndNr);
+      }
     else rndFields.push(field);
 
     this.logger.fatal(`[${rndFields.toString()}]`);

libs/backtracking-lib/src/abstract-backtracker.ts

@@ -0,0 +1,55 @@
+import { Logger } from '@nestjs/common';
+import { IBacktrackingModel } from './backtracking-model.interface';
+
+export abstract class ABacktracker {
+  protected readonly logger = new Logger(this.constructor.name);
+
+  abstract doBacktrack: () => boolean[][];
+
+  protected findSolution = (dataModel: IBacktrackingModel): boolean => {
+    if (dataModel.solved()) return true;
+
+    // nächstes freie Position suchen
+    // const nxtPossPos = dataModel.nextPossiblePosition();
+
+    while (dataModel.nextPossiblePosition()) {
+      dataModel.applyPosition();
+
+      // Lösung mit dem neu konfigurierten dataObject finden
+      const solved: boolean = this.findSolution(dataModel);
+
+      if (solved) return true;
+
+      const afterDiscardedPos = dataModel.discardPosition();
+      this.logger.debug(`afterDiscardedPos: ${afterDiscardedPos}`);
+    }
+
+    return false;
+  };
+
+  protected ___findSolution___ = (dataModel: IBacktrackingModel): boolean => {
+    if (dataModel.solved()) return true;
+
+    // dataModel.options.forEach((option) => {
+    while (dataModel.hasNext()) {
+      // nächstes freie Position suchen
+      const nxtPos = dataModel.nextPosition();
+      this.logger.debug(`nxtPos: ${nxtPos}`);
+
+      // darf die Option hier eingestellt werden ?
+      if (dataModel.positionPossible()) {
+        dataModel.applyPosition();
+
+        // Lösung mit dem neu konfigurierten dataObject finden
+        const solved: boolean = this.findSolution(dataModel);
+
+        if (solved) return true;
+
+        const afterDiscardedPos = dataModel.discardPosition();
+        this.logger.debug(`afterDiscardedPos: ${afterDiscardedPos}`);
+      }
+    }
+
+    return false;
+  };
+}

libs/backtracking-lib/src/backtracker.spec.ts

@@ -1,7 +0,0 @@
-import { Backtracker } from './backtracker';
-
-describe('Backtracker', () => {
-  it('should be defined', () => {
-    expect(new Backtracker()).toBeDefined();
-  });
-});

libs/backtracking-lib/src/backtracker.ts

@@ -1,26 +0,0 @@
-import { IBacktracking } from './backtracking.interface';
-
-export class Backtracker {
-  findSolution = (dataObject: IBacktracking): boolean => {
-    if (dataObject.solved()) return true;
-
-    // nächstes freie Position suchen
-    dataObject.nextPosition();
-
-    dataObject.options().forEach((option) => {
-      // darf die Option hier eingestellt werden ?
-      if (dataObject.positionPossible()) {
-        dataObject.applyPosition();
-
-        // Lösung mit dem neu konfigurierten dataObject finden
-        const solved: boolean = this.findSolution(dataObject);
-
-        if (solved) return true;
-
-        dataObject.discardPosition();
-      }
-    });
-
-    return false;
-  };
-}

libs/backtracking-lib/src/backtracking-model.interface.ts

@@ -1,9 +1,10 @@
 import { MatrixPosition } from './matrix-position';
 
-export interface IBacktracking {
-  options: () => Array<any>;
+export interface IBacktrackingModel {
   solved: () => boolean;
+  hasNext: () => boolean;
   nextPosition: () => MatrixPosition;
+  nextPossiblePosition: () => boolean;
   positionPossible: () => boolean;
   applyPosition: () => MatrixPosition;
   discardPosition: () => MatrixPosition;

package.json

@@ -1,6 +1,6 @@
 {
   "name": "backtracking",
-  "version": "1.0.0",
+  "version": "2.0.0",
   "description": "",
   "author": "",
   "private": true,