1. Variable same name and the meaning is unknown.
Solution: English nomenclature and extended variable name length.
2. The two look alike, but not exactly the same piece of code, copy and paste, forget about small changes.
Solution: Try to write their own.
3. Complete the simulation of large, could not pass the sample, the mentality of the bombing.
Workaround 1: Before the first sample had 'static error'
Solution 2: write function, the breakpoint type debug.
Solution 3: write large simulation, revealing the search, do not fry practice mentality.
4. modulo forget to consider the question negative.
Solution: thinking. . .
5. forgot to turn long long.
The solution: the 'three-year OI get the job, do not open LL ***' as a desktop.
6. forgot to write file
Solution: file written as a function, the expected time to leave 10 to 15 minutes, checking files and folders.
7.MLE
Solution: Check (static error), remember the spatial complexity calculation. . .
First write these, write later encounter.