\[ 2 y(x) y''(x)+y'(x)^2+1=0 \] ✓ Mathematica : cpu = 0.183932 (sec), leaf count = 129
\[\left \{\left \{y(x)\to \text {InverseFunction}\left [e^{2 c_1} \tan ^{-1}\left (\frac {\sqrt {\text {$\#$1}}}{\sqrt {e^{2 c_1}-\text {$\#$1}}}\right )-\sqrt {\text {$\#$1}} \sqrt {e^{2 c_1}-\text {$\#$1}}\& \right ]\left [c_2+x\right ]\right \},\left \{y(x)\to \text {InverseFunction}\left [\sqrt {\text {$\#$1}} \sqrt {e^{2 c_1}-\text {$\#$1}}-e^{2 c_1} \tan ^{-1}\left (\frac {\sqrt {\text {$\#$1}}}{\sqrt {e^{2 c_1}-\text {$\#$1}}}\right )\& \right ]\left [c_2+x\right ]\right \}\right \}\]
✓ Maple : cpu = 0.222 (sec), leaf count = 87
\[ \left \{ -\sqrt {y \left ( x \right ) \left ( {\it \_C1}-y \left ( x \right ) \right ) }+{\frac {{\it \_C1}}{2}\arctan \left ( {1 \left ( y \left ( x \right ) -{\frac {{\it \_C1}}{2}} \right ) {\frac {1}{\sqrt {y \left ( x \right ) \left ( {\it \_C1}-y \left ( x \right ) \right ) }}}} \right ) }-x-{\it \_C2}=0,\sqrt {y \left ( x \right ) \left ( {\it \_C1}-y \left ( x \right ) \right ) }-{\frac {{\it \_C1}}{2}\arctan \left ( {1 \left ( y \left ( x \right ) -{\frac {{\it \_C1}}{2}} \right ) {\frac {1}{\sqrt {y \left ( x \right ) \left ( {\it \_C1}-y \left ( x \right ) \right ) }}}} \right ) }-x-{\it \_C2}=0 \right \} \]