From b41266ed47b531b9c5569af2455d954a588f35d8 Mon Sep 17 00:00:00 2001
From: CortezSMz <cortez_alexandre@hotmail.com>
Date: Tue, 12 Apr 2022 22:41:06 -0300
Subject: [PATCH] implement move exploration order from center to edges

---
 src/engine/Board.ts       |  9 ++++++---
 src/engine/GameManager.ts |  2 +-
 src/engine/Minimax.ts     | 25 +++++++++++++++++++++----
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/src/engine/Board.ts b/src/engine/Board.ts
index 734e683..b6f36f6 100644
--- a/src/engine/Board.ts
+++ b/src/engine/Board.ts
@@ -66,11 +66,14 @@ export class Board {
     return null;
   }
 
-  public allValidLocations(board: GridSlot[][]) {
+  public allValidLocations(
+    board: GridSlot[][],
+    colOrder: number[] = [...Array(this.grid[0].length).keys()]
+  ) {
     const validMoves: GridSlot[] = [];
 
-    for (let i = 0; i < board[0].length; i++) {
-      const isValid = this.isValidLocation(board, i);
+    for (const col of colOrder) {
+      const isValid = this.isValidLocation(board, col);
       if (isValid) validMoves.push(isValid);
     }
 
diff --git a/src/engine/GameManager.ts b/src/engine/GameManager.ts
index 9f2c1a0..d074b42 100644
--- a/src/engine/GameManager.ts
+++ b/src/engine/GameManager.ts
@@ -74,7 +74,7 @@ export default class GameManager {
       this.dropping = false;
 
       setTimeout(() => {
-        this.drop(move[0] || (move as unknown as number));
+        this.drop(move[0]);
       }, 100);
     }
 
diff --git a/src/engine/Minimax.ts b/src/engine/Minimax.ts
index 49eaac1..7685fa7 100644
--- a/src/engine/Minimax.ts
+++ b/src/engine/Minimax.ts
@@ -11,6 +11,7 @@ export class Minimax {
 
     this.depth = 5;
   }
+
   public getBestMove() {
     const [moves, bestScore] = this.getMoves();
 
@@ -26,7 +27,17 @@ export class Minimax {
     return randomBestMove;
   }
 
-  public getMoves(depth: number = this.depth) {
+  private colOrder() {
+    const arr = [...Array(this.manager.board.grid[0].length).keys()];
+
+    return arr.sort(
+      (a, b) =>
+        Math.abs(a - Math.floor(arr.length / 2)) -
+          Math.abs(b - Math.floor(arr.length / 2)) || b - a
+    );
+  }
+
+  private getMoves(depth: number = this.depth) {
     const board = [...this.manager.board.grid];
 
     const moves = this.minimax(board, depth, -Infinity, Infinity, true);
@@ -50,9 +61,12 @@ export class Minimax {
 
     if (playing) {
       const max: (number | number[][])[] = [[], alpha];
-      const validMoves = this.manager.board.allValidLocations(board);
+      const validMoves = this.manager.board.allValidLocations(
+        board,
+        this.colOrder()
+      );
 
-      for (const { row, col, x, z } of validMoves) {
+      for (const { row, col, x, z } of validMoves.sort()) {
         board[row][col].disc = {
           dropped: false,
           color: "YELLOW",
@@ -73,7 +87,10 @@ export class Minimax {
       return max;
     } else {
       const min: (number | number[][])[] = [[], beta];
-      const validMoves = this.manager.board.allValidLocations(board);
+      const validMoves = this.manager.board.allValidLocations(
+        board,
+        this.colOrder()
+      );
 
       for (const { row, col, x, z } of validMoves) {
         board[row][col].disc = {