咱們的小朋友報名參加綜藝“我要上清北”，向導演組提供了在 GitHub 中的源代碼

為了保護孩子的隱私，我不能把各個項目的鏈接貼在此。這些還在小學的小朋友同時提交的有代表性的源代碼還有魔方，帶遞歸的由長方形組成的抽象畫（靈感來自畫家Mondian）等。

下麵是一個例子，這是國際象棋棋子規則的完整代碼，洋洋灑灑500多行，工整漂亮（不好意思，貼在此地就不美觀了，在GitHub網站上看是帶顏色和縮格的），包含了王車易位，吃過路兵，卒子底線升級，將軍，防止本帥被攻擊等等複雜邏輯。

import Foundation
struct ChessBrain: CustomStringConvertible {
var conditionWQueenS: Bool = true
var conditionWKing: Bool = true
var conditionWKingS: Bool = true
var conditionBQueenS: Bool = true
var conditionBKing: Bool = true
var conditionBKingS: Bool = true
var description: String {
/*
0 1 2
0 R . B . . . . .
1 . . . . . . . .
2 . . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
*/
var desc = ""
desc += " 0 1 2 3 4 5 6 7 n"
for row in 0..<8 {
desc += "(row) "
for col in 0..<8 {
if let piece = pieceAt(x: col, y: row) {
switch piece.rank {
case .rook:
desc += piece.isWhite ? "R " : "r "
case .knight:
desc += piece.isWhite ? "N " : "n "
case .bishop:
desc += piece.isWhite ? "B " : "b "
case .king:
desc += piece.isWhite ? "K " : "k "
case .pawn:
desc += piece.isWhite ? "P " : "p "
case .queen:
desc += piece.isWhite ? "Q " : "q "
}
} else {
desc += ". "
}
}
desc += "n"
}
return desc
}
var piecesBox = Set()
var lastMovedPiece: ChessPiece? = nil
mutating func promote(rank: ChessRank) {
guard let movingPawn = lastMovedPiece else {
return
}
var imageName = ""
if movingPawn.isWhite {
switch rank {
case .queen:
imageName = "Queen-white"
case .knight:
imageName = "Knight-white"
case .rook:
imageName = "Rook-white"
case .bishop:
imageName = "Bishop-white"
default:
break
}
} else {
switch rank {
case .queen:
imageName = "Queen-black"
case .knight:
imageName = "Knight-black"
case .rook:
imageName = "Rook-black"
case .bishop:
imageName = "Bishop-black"
default:
break
}
}
piecesBox.remove(movingPawn)
let newPiece = ChessPiece(x: movingPawn.x, y: movingPawn.y, isWhite: movingPawn.isWhite, rank: rank, imageName: imageName)
piecesBox.insert(newPiece)
}
func pieceAt(x: Int, y: Int) -> ChessPiece? {
for piece in piecesBox {
if piece.x == x && piece.y == y {
return piece
}
}
return nil
}
/**
i => ?
0 => 1
1 => 6
2 => ?
3 => ?
*/
mutating func reset() {
piecesBox.removeAll()
for i in 0..<2 {
piecesBox.insert(ChessPiece(x: 0 + i * 7, y: 7, isWhite: true, rank: .rook, imageName: "Rook-white"))
piecesBox.insert(ChessPiece(x: 0 + i * 7, y: 0, isWhite: false, rank: .rook, imageName: "Rook-black"))
}
for i in 0..<2 {
piecesBox.insert(ChessPiece(x: 1 + i * 5, y: 7, isWhite: true, rank: .knight, imageName: "Knight-white"))
piecesBox.insert(ChessPiece(x: 1 + i * 5, y: 0, isWhite: false, rank: .knight, imageName: "Knight-black"))
}
for i in 0..<2 {
piecesBox.insert(ChessPiece(x: 2 + i * 3, y: 7, isWhite: true, rank: .bishop, imageName: "Bishop-white"))
piecesBox.insert(ChessPiece(x: 2 + i * 3, y: 0, isWhite: false, rank: .bishop, imageName: "Bishop-black"))
}
piecesBox.insert(ChessPiece(x: 3, y: 7, isWhite: true, rank: .queen, imageName: "Queen-white"))
piecesBox.insert(ChessPiece(x: 3, y: 0, isWhite: false, rank: .queen, imageName: "Queen-black"))
piecesBox.insert(ChessPiece(x: 4, y: 7, isWhite: true, rank: .king, imageName: "King-white"))
piecesBox.insert(ChessPiece(x: 4, y: 0, isWhite: false, rank: .king, imageName: "King-black"))
for i in 0..<8 {
piecesBox.insert(ChessPiece(x: i, y: 6, isWhite: true, rank: .pawn, imageName: "Pawn-white"))
piecesBox.insert(ChessPiece(x: i, y: 1, isWhite: false, rank: .pawn, imageName: "Pawn-black"))
}
}
func canPieceMove(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
guard let movingPiece = pieceAt(x: frX, y: frY) else {
return false
}
switch movingPiece.rank {
case .rook:
return isValidRook(frX: frX, frY: frY, toX: toX, toY: toY)
case .knight:
return isValidKnight(frX: frX, frY: frY, toX: toX, toY: toY)
case .bishop:
return isValidBishop(frX: frX, frY: frY, toX: toX, toY: toY)
case .king:
return isValidKing(frX: frX, frY: frY, toX: toX, toY: toY)
case .pawn:
return isValidPawn(frX: frX, frY: frY, toX: toX, toY: toY)
case .queen:
return isValidQueen(frX: frX, frY: frY, toX: toX, toY: toY)
}
}
mutating func movePiece(frX: Int, frY: Int, toX: Int, toY: Int) {
if toX > 7 || toX < 0 || toY > 7 || toY < 0 {
return
}
let beCapturedPiece = pieceAt(x: toX, y: toY)
guard let movingPiece = pieceAt(x: frX, y: frY) else {
return
}
if beCapturedPiece?.isWhite == movingPiece.isWhite {
return
}
switch movingPiece.rank {
case .rook:
if !isValidRook(frX: frX, frY: frY, toX: toX, toY: toY) {
return
}
case .knight:
if !isValidKnight(frX: frX, frY: frY, toX: toX, toY: toY) {
return
}
case .bishop:
if !isValidBishop(frX: frX, frY: frY, toX: toX, toY: toY) {
return
}
case .king:
if !isValidKing(frX: frX, frY: frY, toX: toX, toY: toY) {
return
} else {
if isCastling(frX: frX, frY: frY, toX: toX, toY: toY) {
if toX == 6, let castlingRook = pieceAt(x: 7, y: toY) {
piecesBox.remove(castlingRook)
piecesBox.insert(ChessPiece(x: 5, y: toY, isWhite: castlingRook.isWhite, rank: .rook, imageName: castlingRook.imageName))
}
if toX == 2, let castlingRook = pieceAt(x: 0, y: toY) {
piecesBox.remove(castlingRook)
piecesBox.insert(ChessPiece(x: 3, y: toY, isWhite: castlingRook.isWhite, rank: .rook, imageName: castlingRook.imageName))
}
}
}
case .pawn:
if !isValidPawn(frX: frX, frY: frY, toX: toX, toY: toY) {
return
} else {
if let lastMovedPiece = lastMovedPiece {
if isEnPassant(frX: frX, frY: frY, toX: toX, toY: toY) {
piecesBox.remove(lastMovedPiece)
}
}
}
case .queen:
if !isValidQueen(frX: frX, frY: frY, toX: toX, toY: toY) {
return
}
}
if let actualBeCapturedPiece = beCapturedPiece {
piecesBox.remove(actualBeCapturedPiece)
}
if movingPiece.rank == .rook && movingPiece.isWhite == false && movingPiece.x == 0 && movingPiece.y == 0 {
conditionBQueenS = false
}
if movingPiece.rank == .rook && movingPiece.isWhite == false && movingPiece.x == 7 && movingPiece.y == 0 {
conditionBKingS = false
}
if movingPiece.rank == .king && movingPiece.isWhite == false && movingPiece.x == 4 && movingPiece.y == 0 {
conditionBKing = false
}
if movingPiece.rank == .rook && movingPiece.isWhite == true && movingPiece.x == 0 && movingPiece.y == 7 {
conditionWQueenS = false
}
if movingPiece.rank == .rook && movingPiece.isWhite == true && movingPiece.x == 7 && movingPiece.y == 7 {
conditionWKingS = false
}
if movingPiece.rank == .king && movingPiece.isWhite == true && movingPiece.x == 4 && movingPiece.y == 7 {
conditionWKing = false
}
piecesBox.remove(movingPiece)
let movedPiece = ChessPiece(x: toX, y: toY, isWhite: movingPiece.isWhite, rank: movingPiece.rank, imageName: movingPiece.imageName)
piecesBox.insert(movedPiece)
if movedPiece.rank == .pawn && movedPiece.y == 7 || movedPiece.rank == .pawn && movedPiece.y == 0 {
// promote(rank: <#T##ChessRank#>, movingPawn: <#T##ChessPiece#>)
// we'll show a selection dialog window ...
}
lastMovedPiece = movedPiece
}
func needsPromotion() -> Bool {
if let lastMovedPiece = lastMovedPiece, lastMovedPiece.rank == .pawn {
if lastMovedPiece.isWhite {
return lastMovedPiece.y == 0
} else {
return lastMovedPiece.y == 7
}
}
return false
}
func isValidRook(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
return emptyBetween(frX: frX, frY: frY, toX: toX, toY: toY) &&
(frX == toX && frY != toY ||
frX != toX && frY == toY)
}
func isValidKnight(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
return frX + 1 == toX && frY + 2 == toY ||
frX + 2 == toX && frY + 1 == toY ||
frX - 1 == toX && frY + 2 == toY ||
frX - 2 == toX && frY + 1 == toY ||
frX + 1 == toX && frY - 2 == toY ||
frX + 2 == toX && frY - 1 == toY ||
frX - 1 == toX && frY - 2 == toY ||
frX - 2 == toX && frY - 1 == toY
}
func isValidBishop(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
let deltaX = abs(frX - toX)
return emptyBetween(frX: frX, frY: frY, toX: toX, toY: toY) && (frX + deltaX == toX && frY + deltaX == toY ||
frX - deltaX == toX && frY + deltaX == toY ||
frX + deltaX == toX && frY - deltaX == toY ||
frX - deltaX == toX && frY - deltaX == toY)
}
func isValidQueen(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
return isValidRook(frX: frX, frY: frY, toX: toX, toY: toY) ||
isValidBishop(frX: frX, frY: frY, toX: toX, toY: toY)
}
func isValidPawn(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
guard let movingPiece = pieceAt(x: frX, y: frY) else {
return false
}
if isEnPassant(frX: frX, frY: frY, toX: toX, toY: toY) {
return true
}
switch movingPiece.isWhite {
case true:
if let target = pieceAt(x: toX, y: toY) {
// capture
if target.x == movingPiece.x + 1 {
return frX + 1 == toX && frY - 1 == toY
} else if target.x == movingPiece.x - 1 {
return frX - 1 == toX && frY - 1 == toY
} else {
return false
}
} else {
// normal move
if frY == 6 {
return frX == toX && frY - 1 == toY ||
frX == toX && frY - 2 == toY
} else {
return frX == toX && frY - 1 == toY
}
}
case false:
if let target = pieceAt(x: toX, y: toY) {
if target.x == movingPiece.x + 1 {
return frX + 1 == toX && frY + 1 == toY
} else if target.x == movingPiece.x - 1 {
return frX - 1 == toX && frY + 1 == toY
} else {
return false
}
} else {
if frY == 1 {
return frX == toX && frY + 1 == toY ||
frX == toX && frY + 2 == toY
} else {
return frX == toX && frY + 1 == toY
}
}
}
}
func isEnPassant(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
guard let movingPiece = pieceAt(x: frX, y: frY) else {
return false
}
switch movingPiece.isWhite {
case true:
if let deadPiece = pieceAt(x: toX, y: 3), frY == 3, toY == 2, deadPiece.rank == .pawn, lastMovedPiece == deadPiece {
return abs(frX - toX) == 1
}
case false:
if let deadPiece = pieceAt(x: toX, y: 4), frY == 4, toY == 5, deadPiece.rank == .pawn, lastMovedPiece == deadPiece {
return abs(frX - toX) == 1
}
}
return false
}
func isValidKing(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
return canKingAttack(frX: frX, frY: frY, toX: toX, toY: toY) ||
isCastling(frX: frX, frY: frY, toX: toX, toY: toY)
}
func canKingAttack(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
return isValidQueen(frX: frX, frY: frY, toX: toX, toY: toY) && (abs(frX - toX) == 1 || abs(frY - toY) == 1)
}
func isCastling(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
guard let movingPiece = pieceAt(x: frX, y: frY) else {
return false
}
guard abs(frX - toX) == 2,
pieceAt(x: toX, y: toY) == nil,
pieceAt(x: toX - 1, y: toY) == nil else {
return false
}
if toX == 2 {
if pieceAt(x: 3, y: toY) != nil {
return false
}
}
if movingPiece.isWhite {
if !conditionWQueenS && toX == 2 {
return false
} else if !conditionWKingS && toX == 6 {
return false
} else if !conditionWKing {
return false
}
} else {
if !conditionBQueenS && toX == 2 {
return false
} else if !conditionBKingS && toX == 6 {
return false
} else if !conditionBKing {
return false
}
}
if isThreateningCastling(frX: frX, frY: frY, toX: toX, toY: toY) {
return false
}
return true
}
func isThreateningCastling(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
guard let movPiece = pieceAt(x: frX, y: frY) else {
return false
}
if checkIsThreatenedSquare(x: movPiece.x, y: movPiece.y, isWhiteMoving: movPiece.isWhite) ||
checkIsThreatenedSquare(x: (frX + toX) / 2, y: frY, isWhiteMoving: movPiece.isWhite) ||
checkIsThreatenedSquare(x: toX, y: toY, isWhiteMoving: movPiece.isWhite) {
return true
}
return false
}
func checkIsThreatenedSquare(x: Int, y: Int, isWhiteMoving: Bool) -> Bool {
for piece in piecesBox where piece.isWhite != isWhiteMoving {
if piece.rank == .king {
if canKingAttack(frX: piece.x, frY: piece.y, toX: x, toY: y) {
return true
}
} else {
if canPieceMove(frX: piece.x, frY: piece.y, toX: x, toY: y) {
return true
}
}
}
return false
}
func emptyBetween(frX: Int, frY: Int, toX: Int, toY: Int) -> Bool {
let deltaX = abs(frX - toX)
if frX == toX && frY != toY { // |
if toY > frY { // going ??
if frY + 1 <= toY - 1 {
for y in frY + 1 ... toY - 1 {
if pieceAt(x: frX, y: y) != nil {
return false
}
}
}
} else { // going ??
if toY + 1 <= frY - 1 {
for y in toY + 1 ... frY - 1 {
if pieceAt(x: frX, y: y) != nil {
return false
}
}
}
}
} else if frY == toY && frX != toX { // -
if toX > frX { // going ??
if frX + 1 <= toX - 1 {
for x in frX + 1 ... toX - 1 {
if pieceAt(x: x, y: frY) != nil {
return false
}
}
}
} else { // going ??
if toX + 1 <= frX - 1 {
for x in toX + 1 ... frX - 1 {
if pieceAt(x: x, y: frY) != nil {
return false
}
}
}
}
} else if frX + deltaX == toX && frY + deltaX == toY { //
for i in 1.. if pieceAt(x: frX + i, y: frY + i) != nil {
return false
}
}
} else if frX - deltaX == toX && frY + deltaX == toY { // /
for i in 1.. if pieceAt(x: frX - i, y: frY + i) != nil {
return false
}
}
} else if frX + deltaX == toX && frY - deltaX == toY {
for i in 1.. if pieceAt(x: frX + i, y: frY - i) != nil {
return false
}
}
} else if frX - deltaX == toX && frY - deltaX == toY {
for i in 1.. if pieceAt(x: frX - i, y: frY - i) != nil {
return false
}
}
}
return true
}
}