Function getLeft

javascript/0097-interleaving-string.js:183–184

(i, j, s1, s3, tabu)

};

var getLeft = (i, j, s1, s3, tabu) =>
    (tabu[i - 1][j] && s1[i - 1]) === s3[i + j - 1];

var getRight = (i, j, s2, s3, tabu) =>
    (tabu[i][j - 1] && s2[j - 1]) === s3[i + j - 1];