Hubble contest - Tomio's results

1. save traders.length in memory can save gas https://github.com/code-423n4/2022-02-hubble/blob/main/contracts/HubbleViewer.sol#L58 // gas cost 24003

Change to:

uint len = traders.length;
notionalPositions = new uint256[](len);
margins = new int256[](len);
for (uint i = 0; i < len; i++) {

// gas cost 23992

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2. considered using unchecked can save gas https://github.com/code-423n4/2022-02-hubble/blob/main/contracts/HubbleViewer.sol#L306 // gas cost 23796

Change to:

if (totalDTokenSupply > 0) {
            unchecked{
            vUSD = vUSDBalance * dToken / totalDTokenSupply;
            vAsset = vAssetBalance * dToken / totalDTokenSupply;
            }
        }

// gas cost 23080

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3. using multipe require can save gas instead of && https://github.com/code-423n4/2022-02-hubble/blob/main/contracts/MarginAccount.sol#L461 // gas cost 26717

Change to:

require(idx > VUSD_IDX);
require(idx < supportedCollateral, "collateral not seizable");

// gas cost 26709

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