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address-sanitizer

Address sanitizer not working with particular output

I am solving this problem https://codeforces.com/problemset/problem/158/A and I am getting no error with address sanitizer but when the input is n = 1, k = 1 address sanitizer gives error of "heap-buffer-overflow".

My code

int main(int argc, char const *argv[]) {

int n, k;
cin >> n >> k;
int count = 0;
vector<int> v;

while (n) {
    --n;
    int a;
    cin >> a;
    v.push_back(a);
}
int i = 0;

while (i < v.size()) {
    if (v[i] >= v[k] && v[i] > 0) {
        ++count;
    }
    ++i;
}

cout << count << "\n";

return 0;
}
Solution

  • Actually Address sanitizer does work and helpfully detects a bug in your code: you are allocating vector of n elements and then access v[k]. In your case you are trying to access second element (v[1]) of 1-sized vector which causes buffer overflow.