When working on easier problems(like Div1A or Div2B/C), If it took me 10 minutes to get no clues, I would rather jump to some random conclusions that SEEM reasonable. If it passed the examples, I would submit it immediately, spending no time proving my solution. I thought a problem placed at Div1A/Div2B/C couldn't be that hard and I should not waste my time any further. It works and fails from time to time, but more fails on recent contests.

I wonder if some of you guys thought the same way during a contest. Should I give up this strategy anymore?