Suzanne Collins has explained her inspiration for The Hunger Games as watching reality television in which people were competing, and then watching television about the fighting in Iraq. She put the two ideas together which became the core idea of the novel. She also used the Greek myth of Theseus, who found the center of the Crete Labyrinth and killed the Minotaur, as the inspiration for Panem, and for Katniss whom she once described as, "a futuristic Theseus." The sense of loss which Katniss feels at the loss of her father which changes her family's hold on survival comes from Collins's father serving in the Vietnam war where losses were great and feelings ran high even if your own father didn't die. The trilogy is truly amazing, and I agree with your wondering at its inspiration.