Bug: ZuniswapV2Router.sol swapTokensForExactTokens

[zatoichi0826]

function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to
    ) public returns (uint256[] memory amounts) {
        amounts = ZuniswapV2Library.getAmountsIn(
            address(factory),
            amountOut,
            path
        );
        if (amounts[amounts.length - 1] > amountInMax)
            revert ExcessiveInputAmount();
        _safeTransferFrom(
            path[0],
            msg.sender,
            ZuniswapV2Library.pairFor(address(factory), path[0], path[1]),
            amounts[0]
        );
        _swap(amounts, path, to);

for expression if (amounts[amounts.length - 1] > amountInMax)
I thought it would be if (amounts[0] > amountInMax)?

[zatoichi0826]

I think amounts[amounts.length - 1] is the last logic amout input and amounts[0] is the first logic input, and for amountInMax, we need first logic input.