Commit 3b079c0

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Merge pull request amejiarosario#85 from amejiarosario/feat/tree-map-improvements

feat(treeMap): get last entry (highest value)

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Original file line number	Diff line number	Diff line change
`@@ -18,6 +18,11 @@ const Tree = require('../../trees/red-black-tree'); // fast insertion`
`18`	`18`	`* allocate memory beforehand (e.g. HashMap’s initial capacity)`
`19`	`19`	`* nor you have to rehash when is getting full.`
`20`	`20`	`*`
	`21`	`+ * Implementations in other languages:`
	`22`	`+ * Java: https://docs.oracle.com/en/java/javase/15/docs/api/java.base/java/util/TreeMap.html`
	`23`	`+ * C++: https://en.cppreference.com/w/cpp/container/map`
	`24`	`+ * Python: none`
	`25`	`+ *`
`21`	`26`	`*/`
`22`	`27`	`class TreeMap {`
`23`	`28`	`// tag::constructor[]`
`@@ -92,6 +97,22 @@ class TreeMap {`
`92`	`97`	`}`
`93`	`98`	`// end::delete[]`
`94`	`99`
	`100`	`+ /**`
	`101`	`+ * Get the last key/value pair (node with largest key)`
	`102`	`+ */`
	`103`	`+ lastEntry() {`
	`104`	`+ const node = this.tree.getRightmost();`
	`105`	`+ return node ? [node.value, node.data()] : [];`
	`106`	`+ }`
	`107`	`+`
	`108`	`+ /**`
	`109`	`+ * Get the first key/value pair (node with smallest key)`
	`110`	`+ */`
	`111`	`+ firstEntry() {`
	`112`	`+ const node = this.tree.getLeftmost();`
	`113`	`+ return node ? [node.value, node.data()] : [];`
	`114`	`+ }`
	`115`	`+`
`95`	`116`	`// tag::iterators[]`
`96`	`117`	`/**`
`97`	`118`	`* Default iterator for this map`

Lines changed: 43 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,43 @@`
	`1`	`+// some parts tested on src/data-structures/maps/map.spec.js`
	`2`	`+`
	`3`	`+const TreeMap = require('./tree-map');`
	`4`	`+`
	`5`	`+describe('TreeMap: keep values sorted', () => {`
	`6`	`+ let map;`
	`7`	`+`
	`8`	`+ beforeEach(() => {`
	`9`	`+ map = new TreeMap();`
	`10`	`+ });`
	`11`	`+`
	`12`	`+ describe('when map is empty', () => {`
	`13`	`+ describe('.lastEntry and .firstEntry', () => {`
	`14`	`+ it('should get last/first entry', () => {`
	`15`	`+ expect(map.lastEntry()).toEqual([]);`
	`16`	`+ expect(map.firstEntry()).toEqual([]);`
	`17`	`+ });`
	`18`	`+ });`
	`19`	`+ });`
	`20`	`+`
	`21`	`+ describe('when map has entries', () => {`
	`22`	`+ beforeEach(() => {`
	`23`	`+ map.set(20, { title: '3sum', passed: true });`
	`24`	`+ map.set(30, { title: '3sum', passed: false });`
	`25`	`+ map.set(10, { title: '2sum', passed: true });`
	`26`	`+ map.set(5, { title: '4sum', passed: false });`
	`27`	`+ });`
	`28`	`+`
	`29`	`+ describe('.lastEntry and .firstEntry', () => {`
	`30`	`+ it('should get last/first entry', () => {`
	`31`	`+ expect(map.lastEntry()).toEqual([`
	`32`	`+ 30,`
	`33`	`+ { title: '3sum', passed: false },`
	`34`	`+ ]);`
	`35`	`+`
	`36`	`+ expect(map.firstEntry()).toEqual([`
	`37`	`+ 5,`
	`38`	`+ { title: '4sum', passed: false },`
	`39`	`+ ]);`
	`40`	`+ });`
	`41`	`+ });`
	`42`	`+ });`
	`43`	`+});`

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