S2Q2 · Print Pieces Moved from Chess Notation

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⚡ Quick Reference

Type: Full I/O problem

Core idea: split the input into tokens, skip move numbers (ending in .), map each move to a piece name.

piece_map = {'K': 'King', 'Q': 'Queen', 'R': 'Rook',
             'B': 'Bishop', 'N': 'Knight'}

for token in input().split():
    if token.endswith("."):
        continue
    if token.startswith("O"):
        print("King")
        print("Rook")
    else:
        print(piece_map.get(token[0], "Pawn"))

Key rules: - Move numbers end with . -skip them - Castling starts with O -print King then Rook - Uppercase letter at start → named piece via dict lookup - Lowercase letter at start → Pawn

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Problem Statement

Problem (I/O type)

Read a string of chess moves in standard algebraic notation. For each move (ignoring move numbers), print the name of the piece moved. For castling, print both King and Rook.

Example 1:

Input

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. O-O Qc7

Output

Pawn
Pawn
Knight
Knight
Bishop
Pawn
King
Rook
Queen

Example 2:

Input

1. e4 e5 2. O-O O-O-O

Output

Pawn
Pawn
King
Rook
King
Rook

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Understanding the input format

After split(), "1. e4 e5 2. Nf3 Nc6" becomes:

["1.", "e4", "e5", "2.", "Nf3", "Nc6"]
  ↑ skip  ↑ pawn  ↑ pawn  ↑ skip  ↑ knight  ↑ knight

Three categories of token:

Token pattern	Example	Action
Ends with .	"1.", "2."	Skip -it's a move number
Starts with O	"O-O", "O-O-O"	Print King then Rook
Starts with K/Q/R/B/N	"Nf3", "Bb5"	Print the named piece
Starts with lowercase	"e4", "a6"	Print Pawn

Why lowercase = Pawn?

In standard algebraic notation, piece moves always start with an uppercase letter. Pawn moves have no prefix -they start directly with the file letter in lowercase. So anything starting with a lowercase letter is a pawn move.

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Tracing Example 1

Input: "1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. O-O Qc7"

Token	Action	Output
1.	skip	-
e4	lowercase → Pawn	Pawn
e5	lowercase → Pawn	Pawn
2.	skip	-
Nf3	N → Knight	Knight
Nc6	N → Knight	Knight
3.	skip	-
Bb5	B → Bishop	Bishop
a6	lowercase → Pawn	Pawn
4.	skip	-
O-O	castling	King, Rook
Qc7	Q → Queen	Queen

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Solution approaches

Explanatory (if-elif chain)Pythonic (dict.get)Using lambda + filter + map

piece_map = {
    'K': 'King', 'Q': 'Queen', 'R': 'Rook',
    'B': 'Bishop', 'N': 'Knight'
}

moves = input().split()
for token in moves:
    if token.endswith("."):
        continue
    if token.startswith("O"):
        print("King")
        print("Rook")
    elif token[0] in piece_map:
        print(piece_map[token[0]])
    else:
        print("Pawn")

piece_map = {
    'K': 'King', 'Q': 'Queen', 'R': 'Rook',
    'B': 'Bishop', 'N': 'Knight'
}

for token in input().split():
    if token.endswith("."):
        continue
    if token.startswith("O"):
        print("King\nRook")
    else:
        print(piece_map.get(token[0], "Pawn"))

dict.get(key, default) returns "Pawn" when the first character isn't in piece_map. Eliminates the explicit else branch.

piece_map = {
    'K': 'King', 'Q': 'Queen', 'R': 'Rook',
    'B': 'Bishop', 'N': 'Knight'
}

def get_piece(token):
    if token.startswith("O"):
        return "King\nRook"
    return piece_map.get(token[0], "Pawn")

tokens = filter(lambda t: not t.endswith("."), input().split())
print("\n".join(map(get_piece, tokens)))

filter(lambda t: not t.endswith("."), ...) removes move numbers. map(get_piece, ...) converts each token to its piece name(s). "\n".join(...) prints all at once. Fully functional pipeline.

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Key takeaways

01

dict.get(key, default) for safe lookup

piece_map.get(token[0], "Pawn") returns the piece name if the letter is in the map, or "Pawn" if not. Eliminates the explicit else branch.

02

Handle castling before general case

Castling tokens start with O, which isn't in the piece map. Check for castling first with token.startswith("O") before the general lookup.

03

filter() to skip unwanted tokens

filter(lambda t: not t.endswith("."), tokens) cleanly removes move numbers before processing. Separating filtering from processing makes both steps easier to read and test.