Longest Increasing Subsequence

LIS.js

function LIS(arr) {
    var parent = [];
    var lengths = [];
    var globalMaxIndex = 0;
    for(var i=0; i<arr.length; i++) {
        var currMax = -1;
        var currLen = 0;
        for (var j=0; j<i; j++) {
            if (arr[j]<arr[i] && (currMax == -1 || lengths[currMax]< lengths[j])) {
                currMax = j;
            }
        }
        parent.push(currMax);
        if (currMax > -1){
            currLen = lengths[currMax] + 1;
        }
        lengths.push(currLen);
        if (currLen>lengths[globalMaxIndex]) {
            globalMaxIndex = i;
        }
    }
    var result = [];
    do {
        result.push(arr[globalMaxIndex]);
        globalMaxIndex = parent[globalMaxIndex];
    } while (globalMaxIndex > -1);
    return result.reverse();
}
LIS([1,7,3,6,10,2,20,22])