2017ceb1029's blog

Runtime Error on test case 21
By 2017ceb1029, history, 4 years ago, In English

The problem link is : B level And it passes 20 tests but fails on 21st. In an online compiler "CODE" works fine, for the same test case, by failure I mean RUNTIME_ERROR. Any help would be appreciated. The same code first failed at test case 26th, which i noticed was due to less allocated memory when I tripled the allocated space, it fails at 21st case which gives correct output in the other compiler.

Thanks

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4 years ago, # |
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char* c= (char* ) malloc(sizeof(char)*len);
scanf("%s",c);

Pretty sure scanf is based on null terminated strings so you need to allocate 1 more byte.

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    4 years ago, # ^ |
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    NO, i don't think the problem lies there. I had bounded the use of string by len and not using any /0 terminations. The accepted solution uses the same, only change being the next allocation.

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      4 years ago, # ^ |
        Vote: I like it 0 Vote: I do not like it

      Just so you know, it isn't up to you whether or not a null character is placed there. Currently scanf will always write outside of allocated memory. Maybe your runtime error was caused by something else, but that doesn't change the fact that something is being written outside of allocated memory.

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      4 years ago, # ^ |
      ← Rev. 2   Vote: I like it 0 Vote: I do not like it

      I just tried changing

      char* c= (char* ) malloc(sizeof(char)*len);

      into

      char* c= (char* ) malloc(sizeof(char)*(len + 1));

      and now it gets AC.

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