Created
February 8, 2020 10:29
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Heap's Algorithm In Javascript
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const getPermutations = arr => { | |
const output = []; | |
const swapInPlace = (arrToSwap, indexA, indexB) => { | |
const temp = arrToSwap[indexA]; | |
arrToSwap[indexA] = arrToSwap[indexB]; | |
arrToSwap[indexB] = temp; | |
}; | |
const generate = (n, heapArr) => { | |
if (n === 1) { | |
output.push(heapArr.slice()); | |
return; | |
} | |
generate(n - 1, heapArr); | |
for (let i = 0; i < n - 1; i++) { | |
if (n % 2 === 0) { | |
swapInPlace(heapArr, i, n - 1); | |
} else { | |
swapInPlace(heapArr, 0, n - 1); | |
} | |
generate(n - 1, heapArr); | |
} | |
}; | |
generate(arr.length, arr.slice()); | |
return output; | |
}; |
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