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Commit 9874647

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Merge pull request #63 from amejiarosario/hotfix/sorting
Hotfix/sorting
2 parents f484075 + f3fe049 commit 9874647

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7 files changed

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-7
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// Brute force: O(n^2) | O(1)
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function twoSum(nums, target) {
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for (let i = 0; i < nums.length - 1; i++) { // O(n^2)
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for (let j = i + 1; j < nums.length; j++) { // O(n)
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if (nums[i] + nums[j] === target) {
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return [i, j];
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}
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}
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}
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return [];
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}
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module.exports = twoSum;
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// With a HashMap: O(n) | O(n)
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function twoSum(nums, target) {
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const map = nums.reduce((m, v, i) => { // O(n)
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const ids = m.get(v) || [];
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ids.push(i);
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return m.set(v, ids);
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}, new Map());
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for (let i = 0; i < nums.length; i++) { // O(n)
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const diff = target - nums[i];
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if (map.has(diff) && i !== map.get(diff)) {
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return [i, map.get(diff)];
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}
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}
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return [];
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}
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module.exports = twoSum;
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// With a HashMap: O(n) | O(n), 1-pass
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function twoSum(nums, target) {
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const map = new Map();
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for (let i = 0; i < nums.length; i++) { // O(n)
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const complement = target - nums[i];
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if (map.has(complement)) {
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return [map.get(complement), i];
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}
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map.set(nums[i], i);
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}
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return [];
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}
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module.exports = twoSum;
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const assert = require('assert');
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const twoSum = require('./01-two-sum');
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function test() {
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assert.deepEqual(twoSum([1, 2, 3], 4), [0, 2]);
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assert.deepEqual(twoSum([1, 2, 3], 14), []);
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assert.deepEqual(twoSum([2, 2, 2], 4), [0, 1]);
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assert.deepEqual(twoSum(Array(1e7).fill(2), 4), [0, 1]); //
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// assert.deepEqual(twoSum(Array(1e8).fill(2), 4), [0, 1]); // FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory
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// assert.deepEqual(twoSum(Array(1e9).fill(2), 4), [0, 1]); // 1e7 - error 137 - OUT OF MEMORY
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console.log('All tests passed!');
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}
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test();

‎book/content/part04/bubble-sort.asc

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:codedir: ../../../src
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endif::[]
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[[bubble-sort]]
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==== Bubble Sort
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(((Bubble Sort)))
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(((Sorting, Bubble Sort)))

‎book/content/part04/quick-sort.asc

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- <<Online>>: [big]#️❌# No, the pivot element can be choose at random.
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- Recursive: Yes
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- Time Complexity: [big]#✅# <<part01-algorithms-analysis#linearithmic>> _O(n log n)_
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- Space Complexity: [big]#✅# <<part01-algorithms-analysis#constant>> _O(1)_
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- Space Complexity: [big]#✅# <<part01-algorithms-analysis#logarithmic>> _O(log n)_, because of recursion.
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(((Linearithmic)))
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(((Runtime, Linearithmic)))
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(((Space complexity, Constant)))
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(((Space complexity, Logarithmic)))
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// Resources:
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// https://www.khanacademy.org/computing/computer-science/algorithms/quick-sort/a/linear-time-partitioning

‎book/content/part04/sorting-algorithms.asc

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@@ -9,7 +9,7 @@ Sorting is one of the most common solutions when we want to extract some insight
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We can sort to get the maximum or minimum value and many algorithmic problems involves sorting data first.
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.We are going to explore three basic sorting algorithms _O(n^2^)_ which have low overhead:
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- <<part04-algorithmic-toolbox#insertion-sort>>
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- <<part04-algorithmic-toolbox#bubble-sort>>
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- <<part04-algorithmic-toolbox#selection-sort>>
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- <<part04-algorithmic-toolbox#insertion-sort>>
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[cols="20,80"]
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|===
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| Algorithms | Comments
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| <<part04-algorithmic-toolbox#insertion-sort>> | Swap pairs bubbling up largest numbers to the right
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| <<part04-algorithmic-toolbox#bubble-sort>> | Swap pairs bubbling up largest numbers to the right
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| <<part04-algorithmic-toolbox#insertion-sort>> | Look for biggest number to the left and swap it with current
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| <<part04-algorithmic-toolbox#selection-sort>> | Iterate array looking for smallest value to the right
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| <<part04-algorithmic-toolbox#merge-sort>> | Split numbers in pairs, sort pairs and join them in ascending order
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.Sorting algorithms time/space complexity and properties
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|===
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| Algorithms | Avg | Best | Worst | Space | Stable | In-place | Online | Adaptive
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| <<part04-algorithmic-toolbox#insertion-sort>> | O(n^2^) | O(n) | O(n^2^) | O(1) | Yes | Yes | Yes | Yes
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| <<part04-algorithmic-toolbox#bubble-sort>> | O(n^2^) | O(n) | O(n^2^) | O(1) | Yes | Yes | Yes | Yes
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| <<part04-algorithmic-toolbox#insertion-sort>> | O(n^2^) | O(n) | O(n^2^) | O(1) | Yes | Yes | Yes | Yes
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| <<part04-algorithmic-toolbox#selection-sort>> | O(n^2^) | O(n^2^) | O(n^2^) | O(1) | No | Yes | No | No
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| <<part04-algorithmic-toolbox#merge-sort>> | O(n log n) | O(n log n) | O(n log n) | O(n) | Yes | No | No | No
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| <<part04-algorithmic-toolbox#quicksort>> | O(n log n) | O(n^2^) | O(n log n) | O(log n) | Yes | Yes | No | No
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| <<part04-algorithmic-toolbox#quicksort>> | O(n log n) | O(n log n) | O(n^2^) | O(log n) | No | Yes | No | No
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// | Tim sort | O(n log n) | O(log n) | Yes | No | No | Yes
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|===
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// end::table[]
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