用于确定两个字符串最长公共子串的函数

//用于确定两个字符串最长公共子串的函数
        function lcs(word1,word2) {
            var max = 0;
            var index = 0;
            var lcsarr = new Array(word1.length + 1);
            for (var i = 0; i <=word1.length + 1; i++) {
                lcsarr[i] = new Array(word2.length + 1)
                for (var j = 0; j <= word2.length+1; j++) {
                    lcsarr[i][j] = 0;
                }
            }
            for (var i = 0; i <=word1.length; i++) {
                for (var j = 0; j <= word2.length; j++) {
                    if (i == 0 || j == 0) {
                        lcsarr[i][j] = 0;
                    }
                    else {
                        if (word1[i - 1] == word2[j - 1]) {
                              lcsarr[i][j] = lcsarr[i - 1][j - 1] + 1;
                        }
                        else {
                            lcsarr[i][j] = 0;
                        }
                    }
                    if (max < lcsarr[i][j]) {
                        max = lcsarr[i][j];
                        index = i;
                    }
 
                }
            }
            var str = "";
            if (max == 0) {
                return "";
            }
            else
            {
                for (var i = index - max; i <= max; i++) {
                    str += word2[i];
                }
                return str;
            }
        }