Submission #1187926

#	Time	Username	Problem	Language	Result	Execution time	Memory
1187926		baba	Nautilus (BOI19_nautilus)	Pypy 3	0 / 100	159 ms	51116 KiB

nautilus

import numpy as np

def main():
    import sys
    input = sys.stdin.read().split()
    idx = 0
    R = int(input[idx]); idx +=1
    C = int(input[idx]); idx +=1
    M = int(input[idx]); idx +=1
    
    grid = []
    for _ in range(R):
        line = input[idx].strip()
        grid.append( list(line) )
        idx +=1
    commands = input[idx].strip()
    
    # Create water mask
    water_mask = np.zeros((R, C), dtype=bool)
    for i in range(R):
        for j in range(C):
            if grid[i][j] == '.':
                water_mask[i][j] = True
    
    prev_dp = water_mask.copy()
    
    for cmd in commands:
        if cmd == 'N':
            shifted = np.roll(prev_dp, -1, axis=0)
            shifted[-1, :] = False
        elif cmd == 'S':
            shifted = np.roll(prev_dp, 1, axis=0)
            shifted[0, :] = False
        elif cmd == 'E':
            shifted = np.roll(prev_dp, -1, axis=1)
            shifted[:, -1] = False
        elif cmd == 'W':
            shifted = np.roll(prev_dp, 1, axis=1)
            shifted[:, 0] = False
        elif cmd == '?':
            # North shift
            shifted_n = np.roll(prev_dp, -1, axis=0)
            shifted_n[-1, :] = False
            # South shift
            shifted_s = np.roll(prev_dp, 1, axis=0)
            shifted_s[0, :] = False
            # East shift
            shifted_e = np.roll(prev_dp, -1, axis=1)
            shifted_e[:, -1] = False
            # West shift
            shifted_w = np.roll(prev_dp, 1, axis=1)
            shifted_w[:, 0] = False
            shifted = shifted_n | shifted_s | shifted_e | shifted_w
        else:
            shifted = np.zeros_like(prev_dp)
        
        # Apply water mask
        current_dp = shifted & water_mask
        prev_dp = current_dp.copy()
    
    print(np.sum(prev_dp))

if __name__ == "__main__":
    main()

Compilation message (stdout)

Compiling 'nautilus.py'...

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  adding: __main__.pyc (deflated 42%)

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• Subtask 1: 0 / 29
• Subtask 2: 0 / 37
• Subtask 3: 0 / 34