Merge pull request #4692 from stuart-little/stuart-little_125_node

1st commit on 125_node

2 files changed, 78 insertions, 0 deletions

diff --git a/challenge-125/stuart-little/node/ch-1.js b/challenge-125/stuart-little/node/ch-1.js
new file mode 100755
index 0000000000..e779fc8023
--- /dev/null
+++ b/challenge-125/stuart-little/node/ch-1.js
@@ -0,0 +1,27 @@
+#!/usr/bin/env node
+
+// run <script> <number>
+
+function trps(n) {
+    let triples=[]
+    for (let i=1; i<=Math.floor((n+1)/2); i++) {
+	let sqDif = Math.floor(Math.sqrt(n**2-i**2))
+	if ((i<n) && (i**2+sqDif**2==n**2)) {
+	    triples.push([i,sqDif,n])
+	}
+    }
+    for (let i=1; i<n; i++) {
+	if ((n**2 % i == 0) && ((i%2) === ((Math.floor(n**2/i))%2))) {
+	    let s = Math.floor(n**2/i)
+	    triples.push([Math.floor((s-i)/2), n, Math.floor((s+i)/2)])	    
+	}
+    }
+    return triples
+}
+
+const sol = trps(parseInt(process.argv[2]));
+if (sol.length>0) {
+    sol.forEach(x => console.log(x));
+    process.exit()
+}
+console.log(-1)
diff --git a/challenge-125/stuart-little/node/ch-2.js b/challenge-125/stuart-little/node/ch-2.js
new file mode 100755
index 0000000000..500019c150
--- /dev/null
+++ b/challenge-125/stuart-little/node/ch-2.js
@@ -0,0 +1,51 @@
+#!/usr/bin/env node
+
+const { maxBy } = require('lodash')
+
+function lr(tree) {
+    if (tree.length < 3 || tree[0] === '.') { return [[],[]] }        
+    if (tree.length === 3) { return [["."],["."]] }        
+    left=[]
+    let [sm,ix] = [0,1]
+    while (sm !== -1) { 
+        left.push(tree[ix])
+        sm+=(tree[ix] == '.' ? -1 : 1)
+        ix+=1
+    }
+    return [left,tree.slice(left.length+1)]
+}
+
+function lrLongPath(tree) {
+    if (tree[0] === '.') { return [[],[]] }        
+    if (tree.length === 3) { return [[tree[0]],[tree[0]]] }        
+    return lr(tree).map( ar => [tree[0], ...maxBy(lrLongPath(ar), x => x.length)] )
+}
+
+function biLongPath(tree) {
+    if (tree.length < 3 || tree[0] == '.') { return [] }
+    if (tree.length === 3) { return [tree[0]] }
+    let [lPath,rPath] = lrLongPath(tree)
+    let path = [...([...(lPath.slice(1))].reverse()),...rPath]
+    let [left,right] = lr(tree)
+    return maxBy([path, ...[left,right].map(biLongPath)], x => x.length)
+}
+
+console.log(biLongPath(process.argv.slice(2)).join(" "))
+
+/*
+run <script> <tree in preorder form with '.' for empty nodes, entered as space-separated values>
+
+ref: https://stackoverflow.com/a/2676849/11064961
+
+e.g. 1 2 4 . 7 . . . 3 5 . . 6 . . represents the tree
+
+        1
+       / \
+      2   3
+     /   / \
+    4   5   6
+     \
+      7
+
+given as an example in the problem formulation at https://perlweeklychallenge.org/blog/perl-weekly-challenge-113/#TASK2
+*/