Data update

Task/Lychrel-numbers/JavaScript/lychrel-numbers.js

@@ -0,0 +1,52 @@
+  const bigInt = require('big-integer');
+  const cache = new Map();
+  function rev(bi) {
+      const s = bi.toString().split('').reverse().join('');
+      return bigInt(s);
+  }
+  function lychrel(n) {
+      if (cache.has(n.toString())) { // bigInt 是对象，需要用字符串作为 Map 的键
+          return cache.get(n.toString());
+      }
+      let r = rev(n);
+      let res = { flag: true, bi: n };
+      const seen = [];
+      for (let i = 0; i < 500; i++) {
+          n = n.add(r);
+          r = rev(n);
+          if (n.equals(r)) {
+              res = { flag: false, bi: bigInt(0) };
+              break;
+          }
+          if (cache.has(n.toString())) {
+              res = cache.get(n.toString());
+              break;
+          }
+          seen.push(n);
+      }
+      for (const bi of seen) {
+          cache.set(bi.toString(), res);
+      }
+      return res;
+  }
+  const seeds = [];
+  const related = [];
+  const palin = [];
+  for (let i = 1; i <= 10000; i++) {
+      const n = bigInt(i);
+      const t = lychrel(n);
+      if (!t.flag) {
+          continue;
+      }
+      if (n.equals(t.bi)) {
+          seeds.push(t.bi);
+      } else {
+          related.push(t.bi);
+      }
+      if (n.equals(t.bi)) {
+          palin.push(t.bi);
+      }
+  }
+  console.log(`${seeds.length} Lychrel seeds: [${seeds.map(s => s.toString()).join(', ')}]`);
+  console.log(`${related.length} Lychrel related`);
+  console.log(`${palin.length} Lychrel palindromes: [${palin.map(p => p.toString()).join(', ')}]`);