Was it a flood that wiped out the dinos?

No. Dinosaurs succumbed to extinction due to what scientists believe would have been one or more catastrophic events such as increased volcanic activity and massive asteroid impacts that devastated the Earth at the end of the Mesozoic era. While the dinos were going into what would have been their Cenozoic Era, something known as the Cretacious-Tertiary extinction event occured. These events are believed to have critically disarrayed the planet's natural habitability due to altered sunlight which detrimented the photosynthesis pattern that occurs in plant life. It is unquestionable that this is what was the scientific end of dinosaurs.