Solidity Arrays – Fixing Invalid Array Length Error

"Invalid jump destination" is generated when you access an array out of bounds. Did you try debugging it in mix?

The following code seems to work. By using the keyword storage in the argument type you can pass a storage reference (only works for internal functions and libraries), otherwise the storage data would be copied to memory. As an optimization you might consider copying the storage array to memory, checking whether it is sorted, if not, sort it and copy it back to storage. Another potential pitfall concerning browser-solidity: You have to enter array arguments as [1,7,4,5].

Oh and the best optimization is of course to sort the array off-chain and only check on-chain whether it is sorted or not.

// SPDX-License-Identifier: MIT
pragma solidity ^0.7.0;


function quickSort(uint[] memory arr, int left, int right) pure {
    int i = left;
    int j = right;
    if (i == j) return;
    uint pivot = arr[uint(left + (right - left) / 2)];
    while (i <= j) {
        while (arr[uint(i)] < pivot) i++;
        while (pivot < arr[uint(j)]) j--;
        if (i <= j) {
            (arr[uint(i)], arr[uint(j)]) = (arr[uint(j)], arr[uint(i)]);
            i++;
            j--;
        }
    }
    if (left < j)
        quickSort(arr, left, j);
    if (i < right)
        quickSort(arr, i, right);
}

contract QuickSort {
    function sort(uint[] memory data) public pure returns (uint[] memory) {
        quickSort(data, int(0), int(data.length - 1));
        return data;
    }
}

Edit (2020-10): Underflow problem fixed by @subhodi and updated to latest Solidity version.

uint256 size = 10;

function initArray() public pure {
    uint256[][] memory arr = new uint256[][](size);
    for (uint i; i < size; i++) {
        arr[i] = new uint256[](size);
    }
    // ...
}

The issue in above code is you are trying to access storege variable size in pure function initArray which is not possible. You should understand the difference between view and pure function. A view function will read the storage but will not change it and a pure function does not need access to the storage and will not change it.

I tried the following code to achieve what you expect but while executing initArray function I am getting VM exception.

pragma solidity ^0.4.24;

contract Foo {
    uint256 n = 10;
    function initArray() public view  {
        uint[][] memory result = new uint[][](n*n);
        for (uint i = 0; i < n; i++){
            for(uint j = 0; j < n; j++){
                result[i][j] = 1;
            }
        }

    }
}

You can achieve the functionality of 2D arrays using a 1D array as following and it is working as expected

pragma solidity ^0.4.24;

contract Foo {
    uint256 n = 10;
    function initArray() public view  {
        uint[] memory result = new uint[](n*n);
        for (uint i = 0; i < n; i++){
           for(uint j = 0; j < n; j++){
                result[(i*9)+j]=1; 
            }
        }

    }
}

I am able to create 2D array in memory. Please refer the following code for the same :

pragma solidity ^0.4.24;

contract Foo {
    uint256 n = 10;
    function initArray(uint k,uint l) public view returns(uint)  {
        uint[][] memory arr = new uint[][](n);
        for (uint i=0; i < n; i++) {
            uint[] memory temp = new uint[](n);
            for(uint j = 0; j < n; j++){
                    temp[j]=i+j; 
                }
            arr[i] = temp;
        }
        // ...
        return arr[k][l];
    }
}

Hope it helps!