Next lexicographically word

next-lexicographically.groovy

def makeItLarge(inputs) {
    inputs.collect { input ->
        nextLexicographically(input)
    }
}

def nextLexicographically(input) {
    def queue = new java.util.PriorityQueue<Character>()
    def a = input.toCharArray()
    def pivot = -1
    
    def i
    for (i = a.length - 1; i > 0 && pivot == -1; i--) {
        if (a[i] > a[i - 1]) {
            pivot = i - 1;
            queue.offer(a[i - 1])
        }
        queue.offer(a[i]);
    }
    
    if (pivot == -1) return "no answer";
    
    def target = a[pivot];
    while(queue.size() > 0) {
        def next = queue.poll()
        if (next > target) {
            a[pivot] = next;
            while(queue.size() > 0) a[i++] = queue.poll();
        } else {
            a[i++] = queue.poll();
        }
    }
    
    return new String(a);
}

makeItLarge(["abcde", "edcba", "cacba"])