language agnostic - Code Golf: Ghost Leg -

the challenge

the shortest code character count output numeric solution, given number , valid string pattern, using ghost leg method.

examples

 input: 3, "| | | | | | | |  |-| |=| | | | |  |-| | |-| |=| |  | |-| |-| | |-|"  output: 2  input: 2, "| | |=| |  |-| |-| |  | |-| | |"  output: 1 

clarifications

1. do not bother input. consider values given somewhere else.
2. both input values valid: column number corresponds existing column , pattern contains symbols |, -, = (and [space], [lf]). also, 2 adjacent columns cannot both contain dashes (in same line).
3. the dimensions of pattern unknown (min 1x1).

clarifications #2

1. there 2 invalid patterns: |-|-| , |=|=| create ambiguity. given input string never contain those.
2. the input variables same all; numeric value , string representing pattern.
3. entrants must produce function.

test case

 given pattern: "|-| |=|-|=|lf| |-| | |-|lf|=| |-| | |lf| | |-|=|-|"  |-| |=|-|=| | |-| | |-| |=| |-| | | | | |-|=|-|  given value : expected result  1 : 6  2 : 1   3 : 3  4 : 5  5 : 4  6 : 2 

edit: corrected expected results

javascript: 169 158 148 141 127 125 123 122 characters

minified , golfed:

function g(n,s){for(l=s.split('\n'),n*=2;k=l.shift();)for(j=3;j;)n+=k[n-3]==(c=--j-1?'=':'-')?-2:k[n-1]==c?2:0;return n/2} 

readable version:

function g(n, str) {    var c, i, j;    var lines = str.split('\n');    n = (n * 2) - 2;     (i = 0; < lines.length; i++) {       (j = 0; j < 3; j++) {          c = (j == 1) ? '-' : '=';           if (lines[i].charat(n-1) == c) n-=2;          // move left          else if (lines[i].charat(n+1) == c) n+=2;     // move right       }    }     return 1+n/2; } 

explanation:

1. str split array of lines.
2. n scaled cover number of characters in each line, starting 0.
3. iterate 3 times on each line: 1 time each layer. imagine each line divided 3 layers: top , bottom layers legs of of = sign attached. middle layer legs of - signs.
4. move n either left or right according adjacent signs. there 1 possible move every layer of each line. therefore n move 3 times in line.
5. return n, normalized start 1 number of vertical lines.

test cases:

var ghostlegs = [];  ghostlegs[0] = "|-| |=|-|=|\n" +                "| |-| | |-|\n" +                "|=| |-| | |\n" +                "| | |-|=|-|";  ghostlegs[1] = "| | | | | | | |\n" +                "|-| |=| | | | |\n" +                "|-| | |-| |=| |\n" +                "| |-| |-| | |-|";  ghostlegs[2] = "| | |=| |\n" +                "|-| |-| |\n" +                "| |-| | |";  ghostlegs[3] = "|=|-|";  (var m = 0; m < ghostlegs.length; m++) {    console.log('\ntest: ' + (m + 1) + '\n');     (var n = 1; n <= (ghostlegs[m].split('\n')[0].length / 2) + 1; n++) {       console.log(n + ':' + g(n, ghostlegs[m]));    } } 

results:

test: 1 1:6 2:1 3:3 4:5 5:4 6:2  test: 2 1:1 2:3 3:2 4:4 5:5 6:6 7:8 8:7  test: 3 1:3 2:1 3:4 4:2 5:5  test: 4 1:3 2:2 3:1