Duplicate character problem

#1

*** Error in `/testcase15634974/execdir/program’: free(): invalid pointer: 0x00007ffc395433b8 ***
what does this error mean?

#2

@manmeetkahlon hi,aisi to koi error nhi arhi ab ,woh apne input me 5 element die hue the jabki 3 ane the,input check kro.