Done with maximum pair sum.

Author: simdi

list/max-pair-sum/index.js

@@ -0,0 +1,41 @@
+/*
+* @author: Chisimdi Damian Ezeanieto
+* @date: 23/01/2020
+*/
+
+const MaxPairNumberSum = (arr) => {
+  /*
+  * Steps: 
+  * 1. Define, 2. Represent, 3. Approach/Strategy, 4. Algorithm, 5. Analyse, 6. Experiment
+  */
+  // ([51, 71, 17, 42])).toEqual([51, 42]) 
+  // pick pairs, calculate digits, compare pairs
+  let i = 0;
+  let max = 0;
+  let pair = [];
+  while(i < (arr.length - 1)) {
+    let j = i + 1;
+    let jLength = arr.slice(j);
+    while(j < jLength.length) {
+      let iItem = arr[i];
+      let jItem = jLength[j];
+      let addIDigit = (iItem).toString().split('').reduce((a, b) => a+Number(b), 0);
+      let addJDigit = (jItem).toString().split('').reduce((a, b) => a+Number(b), 0);
+      if (addIDigit === addJDigit) {
+        max = Math.max((iItem + jItem), max);
+        pair.push(iItem, jItem);
+      }
+      // Keep max
+      j++;
+    }
+    i++;
+  }
+
+  if (pair.length > 0) {
+    return pair;
+  }
+
+  return -1;
+}
+
+module.exports = MaxPairNumberSum;

list/max-pair-sum/test.js

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+/*
+* @author: Chisimdi Damian Ezeanieto
+* @date: 23/01/2020
+*/
+const maxPairNumberSum = require('./index');
+test('maxPairNumberSum is a function', () => {
+  expect(typeof maxPairNumberSum).toEqual('function');
+});
+test('maxPairNumberSum [51, 71, 17, 42] to give [51, 42]', () => {
+  expect(maxPairNumberSum([51, 71, 17, 42])).toEqual([51, 42]);
+});
+test('maxPairNumberSum [42, 33, 60] to give [42, 60]', () => {
+  expect(maxPairNumberSum([42, 33, 60])).toEqual([42, 60]);
+});
+test('maxPairNumberSum [51, 32, 43] to give -1', () => {
+  expect(maxPairNumberSum([51, 32, 43])).toEqual(-1);
+});