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Commit d267d72

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ohepworthbelltrekhleb
authored andcommitted
Added fibonacci sequence as well as fibonacci nth, renamed functions accordingly (trekhleb#36)
1 parent a63bc67 commit d267d72

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4 files changed

+59
-27
lines changed

4 files changed

+59
-27
lines changed

‎src/algorithms/math/fibonacci/__test__/fibonacci.test.js‎

Lines changed: 8 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -2,14 +2,13 @@ import fibonacci from '../fibonacci';
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describe('fibonacci', () => {
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it('should calculate fibonacci correctly', () => {
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expect(fibonacci(1)).toBe(1);
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expect(fibonacci(2)).toBe(1);
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expect(fibonacci(3)).toBe(2);
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expect(fibonacci(4)).toBe(3);
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expect(fibonacci(5)).toBe(5);
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expect(fibonacci(6)).toBe(8);
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expect(fibonacci(7)).toBe(13);
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expect(fibonacci(8)).toBe(21);
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expect(fibonacci(20)).toBe(6765);
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expect(fibonacci(1)).toEqual([1]);
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expect(fibonacci(2)).toEqual([1, 1]);
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expect(fibonacci(3)).toEqual([1, 1, 2]);
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expect(fibonacci(4)).toEqual([1, 1, 2, 3]);
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expect(fibonacci(5)).toEqual([1, 1, 2, 3, 5]);
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expect(fibonacci(6)).toEqual([1, 1, 2, 3, 5, 8]);
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expect(fibonacci(7)).toEqual([1, 1, 2, 3, 5, 8, 13]);
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expect(fibonacci(8)).toEqual([1, 1, 2, 3, 5, 8, 13, 21]);
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});
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});
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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
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import fibonacciNth from '../fibonacciNth';
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describe('fibonacciNth', () => {
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it('should calculate fibonacci correctly', () => {
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expect(fibonacciNth(1)).toBe(1);
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expect(fibonacciNth(2)).toBe(1);
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expect(fibonacciNth(3)).toBe(2);
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expect(fibonacciNth(4)).toBe(3);
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expect(fibonacciNth(5)).toBe(5);
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expect(fibonacciNth(6)).toBe(8);
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expect(fibonacciNth(7)).toBe(13);
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expect(fibonacciNth(8)).toBe(21);
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expect(fibonacciNth(20)).toBe(6765);
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});
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});
Lines changed: 16 additions & 18 deletions
Original file line numberDiff line numberDiff line change
@@ -1,26 +1,24 @@
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// Calculate fibonacci number at specific position using Dynamic Programming approach.
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export default function fibonacci(numberPosition) {
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if (numberPosition === 1) {
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return 1;
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}
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// Return a fibonacci sequence as an array
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export default function fibonacci(n) {
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const fibSequence = [1];
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let currentValue = 1;
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let previousValue = 0;
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let iterationsCounter = numberPosition - 1;
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if (n === 1) {
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return fibSequence;
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}
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// Calculated fibonacci number.
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let fib = null;
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// Previous fibonacci number.
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let fibPrev = 1;
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// Before previous fibonacci number.
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let fibPrevPrev = 0;
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let iterationsCounter = n - 1;
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while (iterationsCounter) {
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// Calculate current value using two previous ones.
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fib = fibPrev+fibPrevPrev;
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// Shift previous values.
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fibPrevPrev=fibPrev;
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fibPrev=fib;
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currentValue+=previousValue;
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previousValue = (currentValue-previousValue);
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fibSequence.push(currentValue);
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iterationsCounter -= 1;
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}
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return fib;
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return fibSequence;
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}
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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,20 @@
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// Calculate fibonacci number at specific position using Dynamic Programming approach.
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export default function fibonacciNth(n) {
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let currentValue = 1;
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let previousValue = 0;
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if (n === 1) {
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return 1;
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}
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let iterationsCounter = n - 1;
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while (iterationsCounter) {
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currentValue += previousValue;
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previousValue = (currentValue - previousValue);
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iterationsCounter -= 1;
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}
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return currentValue;
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}

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