js-concepts: leetcode prob.525 - Contiguous array, parallel with async utility

Author: baochau.dinh

LeetCode/525. Contiguous Array/index.js

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+/**
+ * Given a binary array of [0, 1], return the maximum length of a contiguous subarray with equal number 1 and 0
+ * 
+ * 1 0 0 1 0 1
+ * 0 0 0 1 0 1
+ * 
+ */
+
+var findMaxLength = function(nums) {
+  if (nums.length < 2) return 0;
+  let sum = [];
+  let map = {};
+  let result = 0;
+
+  for (let i = 0; i < nums.length; i++) {
+    if (nums[i] === 0) sum[i] = (sum[i - 1] || 0) - 1;
+    if (nums[i] === 1) sum[i] = (sum[i - 1] || 0) + 1;
+  }
+  console.log('sum: ', sum);
+
+  for (let i = 0; i < sum.length; i++) {
+    if (map[sum[i]] === undefined) {
+      map[sum[i]] = i;
+    }
+  }
+  console.log('map: ', map);
+
+  for (let i = 0; i < sum.length; i++) {
+    if (sum[i] === 0) {
+      result = Math.max(result, i + 1);
+    } else {
+      result = Math.max(result, i - map[sum[i]])
+    }
+  }
+
+  return result;
+};
+
+console.log(findMaxLength([1, 0, 0, 1, 0, 1]));

Parallel/index.js

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+const async = require('async');
+
+async.parallel([
+  function(callback) {
+    setTimeout(function() {
+      console.log('Task one');
+      callback(null, 1);
+    }, 200);
+  },
+
+  function(callback) {
+    setTimeout(function() {
+      console.log('Task two');
+      callback(null, 2);
+    }, 100);
+  }
+],
+function(err, results) {
+  console.log(results);
+});