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Copy path31-nextPermutation.js
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31-nextPermutation.js
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/**
* @param {number[]} nums
* @return {void} Do not return anything, modify nums in-place instead.
*/
// var nextPermutation = function (nums) {
// if (nums.)
// let convertArrayToNum = (arr) => {
// let result = 0;
// for (let i = 0; i < arr.length; i++) {
// result *= 10;
// result += arr[i];
// }
// return result;
// };
// let findAllPermutations = (arr) => {
// let allPermutations = [];
// let findAllPermutationsRecursively = (arr, toAdd) => {
// if (arr.length === 0) {
// allPermutations.push(toAdd);
// }
// for (let i = 0; i < arr.length; i++) {
// let num = toAdd * 10 + arr[i];
// let newArr = arr
// .slice(0, i)
// .concat(arr.slice(i + 1, arr.length));
// findAllPermutationsRecursively(newArr, num);
// }
// };
// findAllPermutationsRecursively(arr, 0);
// return allPermutations;
// };
// let mergeSort = function (array) {
// let merge = function (firstArray, secondArray) {
// let i = 0;
// let j = 0;
// let result = [];
// while (true) {
// if (firstArray[i] < secondArray[j]) {
// result.push(firstArray[i]);
// i++;
// } else {
// result.push(secondArray[j]);
// j++;
// }
// if (i === firstArray.length) {
// return result.concat(
// secondArray.slice(j, secondArray.length)
// );
// } else if (j === secondArray.length) {
// return result.concat(
// firstArray.slice(i, firstArray.length)
// );
// }
// }
// };
// if (array.length === 1) {
// return array;
// }
// const middleIndex = Math.floor(array.length / 2);
// const firstArray = mergeSort(array.slice(0, middleIndex));
// const secondArray = mergeSort(array.slice(middleIndex, array.length));
// const merged = merge(firstArray, secondArray);
// return merged;
// };
// let convertNumToArray = (num) => {
// let result = [];
// while (num !== 0) {
// let remainder = num % 10;
// num = Math.floor(num / 10);
// result = [remainder].concat(result);
// }
// return result;
// };
// let sortedPermutations = mergeSort(findAllPermutations(nums));
// let num = convertArrayToNum(nums);
// let index = sortedPermutations.indexOf(num);
// if (index + 1 === sortedPermutations.length) {
// index = 0;
// } else {
// index++;
// }
// let nextNum = sortedPermutations[index];
// return convertNumToArray(nextNum);
// };
let nextPermutation = function (nums) {
let mergeSort = function (array) {
let merge = function (firstArray, secondArray) {
let i = 0;
let j = 0;
let result = [];
while (true) {
if (firstArray[i] < secondArray[j]) {
result.push(firstArray[i]);
i++;
} else {
result.push(secondArray[j]);
j++;
}
if (i === firstArray.length) {
return result.concat(
secondArray.slice(j, secondArray.length)
);
} else if (j === secondArray.length) {
return result.concat(
firstArray.slice(i, firstArray.length)
);
}
}
};
if (array.length === 1) {
return array;
}
const middleIndex = Math.floor(array.length / 2);
const firstArray = mergeSort(array.slice(0, middleIndex));
const secondArray = mergeSort(array.slice(middleIndex, array.length));
const merged = merge(firstArray, secondArray);
return merged;
};
for (let i = nums.length - 1; i >= 0; i--) {
let first = nums[i];
let second = nums[i - 1];
if (!second && second !== 0) {
let sorted = mergeSort(nums);
console.log("here");
for (let i = 0; i < nums.length; i++) {
nums[i] = sorted[i];
}
return nums;
}
if (first > second) {
let secondHalf = mergeSort(nums.slice(i, nums.length));
nums[i - 1] = secondHalf.find((el) => el > second);
let firstHalf = nums.slice(0, i);
let index = secondHalf.indexOf(nums[i - 1]);
secondHalf[index] = second;
for (let i = 0; i < nums.length; i++) {
nums[i] = firstHalf.concat(mergeSort(secondHalf))[i];
}
return nums;
}
}
};
console.log(nextPermutation([2, 2, 0, 4, 3, 1]));