segment fault

SIGSEGV --- Segment Fault. The possible cases of your encountering this error are:
1.buffer overflow --- usually caused by a pointer reference out of range.
2.stack overflow --- please keep in mind that the default stack size is 8192K.
3.illegal file access --- file operations are forbidden on our judge system.

core文件
ulimit -a //可以查看core文件的大小
core file size (blocks, -c) 0 //如果是0，那么需要解除大小限制
ulimit -c unlimited //解除对core的大小的限制
如果生成的core后面没有尾缀，不容易区分，让生成的core文件带上pid
su //如果不行 就sudo password
echo "1" > /proc/sys/kernel/core_uses_pid