Longest Common Substring

gistfile1.js

// via. http://en.wikibooks.org/wiki/Algorithm_implementation/Strings/Longest_common_substring#Python
function LCSubstr_str(S, T) {
    var m = S.length, n = T.length;
    var L = [], ml = m + 1, nl = n + 1;
    for (var i = 0; i < ml; i++) {
        var l = [];
        for (var j = 0; j < nl; j++) {
            l.push(0);
        };
        L.push(l);
    };
    var LCS = "";
    var longest = 0;
    for (var i = 0; i < m; i++) {
        for (var j = 0; j < m; j++) {
            if (S.charAt(i) == T.charAt(j)) {
                var v = L[i][j] + 1;
                L[i + 1][j + 1] = v;
                if (v > longest) {
                    longest = v;
                    LCS = "";
                };
                if (v == longest) {
                    LCS += S.slice(i - v + 1, i + 1);
                };
            };
        };
    };
    return LCS;
};