In response to Rachel's question about whether Hashem gave Noach's
generation time to repent, the answer is a most certain YES!
First, Hashem waited 10 generations from Adam until Noach to bring the
flood. The ills of Noach's generation, while the worst of all, were not
unique. All previous generations also sinned. Hashem waited 10
generations to give the world a chance to do teshuva (repent). Only then
did Hashem decide to bring the Mabul.
Second, even after Hashem decided to destroy the world, it took Noach 120
years to build the ark. Hashem wanted it to take so long so people would
hear about the impending doom and repent. The medrash tells us that Noach
was asked constantly "what are you building?" When he would tell the
world about the coming flood, they just laughed at him.
As we say in the Yom Kipper prayers, Hashem doesn't want to kill the
sinner, only to see them repent and return from their evil ways.