day12_1.groovy

def theMap = [
    "fw-ll", "end-dy", "tx-fw", "tx-tr", "dy-jb", "ZD-dy", "dy-BL", "dy-tr", "dy-KX", "KX-start", "KX-tx", "fw-ZD", "tr-end", "fw-jb", "fw-yi", "ZD-nr", "start-fw", "tx-ll", "ll-jb", "yi-jb", "yi-ll", "yi-start", "ZD-end", "ZD-jb", "tx-ZD",
]

caves = [:]
theMap.each { connection ->
    def a = connection.split('-')[0]
    def b = connection.split('-')[1]
    if (!caves[a]) {
        caves[a] = [b]
    } else {
        caves[a] << b
    }
    if (!caves[b]) {
        caves[b] = [a]
    } else {
        caves[b] << a
    }
}

totalPath = 0

findPaths('start')

totalPath

def findPaths(theCave, path=[]) {
    path << theCave
    caves[theCave].each { cave ->
        if (cave == 'end') {
            println(path)
            totalPath += 1
            return
        }
        if (cave[0] > 'Z' && cave in path) {
            return
        }
        findPaths(cave, path)
    }
    path.remove(path.size()-1)
}