Aug'14 FP(FP) contest entry of thedeemon

gistfile1.d

module main;
import std.stdio, std.range, std.algorithm, std.string, std.typecons;

enum W = 3;
enum H = 5;
char[W][H][10] symbols = [["111", "101", "101", "101", "111"], ["110", "010", "010", "010", "111"], 
["111", "001", "111", "100", "111"], ["111", "001", "111", "001", "111"], ["101", "101", "111", "001", "001"], 
["111", "100", "111", "001", "111"], ["111", "100", "111", "101", "111"], ["111", "001", "011", "010", "010"], 
["111", "101", "111", "101", "111"], ["111", "101", "111", "001", "111"]];

class MatrixReader { // range of ranges of (line, pos, range of strings); holds just H lines in memory
    File f;
    string[H] lines;
    int curline;

    this(string fname) {
        f = File(fname, "r");
        foreach(i; 0..H) lines[i] = f.readln.strip;        
    }

    auto front() { return iota(lines[0].length-W+1).map!(x => tuple(curline, x, iota(H).map!(y => lines[y][x .. x+W]))); }
    bool empty() { return lines[H-1].length==0; }
    void popFront() {
        delete lines[0];
        foreach(i; 0..H-1) lines[i] = lines[i+1];
        lines[H-1] = f.readln.strip;        
        curline++;
    }
}

int whatDigit(R)(R r) {    
    foreach(i; 0..10)
        if (equal(r.save, symbols[i][])) return i;
    return -1;
}

void main(string[] argv) {
    foreach(t;  new MatrixReader("matrix.txt").joiner.map!(t => tuple(t[0], t[1], whatDigit(t[2]))).filter!(t => t[2] >= 0))
        writeln("line: ", t[0], " col: ", t[1], " digit: ", t[2]);
}