leetcode

前言

https://github.com/soulmachine/leetcode

Remove Duplicates from Sorted Array

Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length. Do not allocate extra space for another array, you must do this in place with constant memory. For example, Given input array A = [1,1,2], Your function should return length = 2, and A is now [1,2].

int removeDuplicates(int A[], int n) {
  if (n <= 0) return 0;

  int len = 0;
  for (int i = 1; i < n; ++i) {
   if (A[len] != A[i-1]) A[++len] = A[i];
  }
  return len + 1;
}

使用c++标准库函数, std::unique std::distance

int removeDuplicates(int A[], int n) {
  return std::distance(A, std::unique(A, A + n));
}

使用std::upper_bound进一步扩展 

int removeDuplicates(int A[], int n) {
  return removeDuplicates(A, A + n, A) - A;
}
template<typename InIt, typename OutIt>
OutIt removeDuplicates(InIt first, InIt last, OutIt output) {
  while (first != last) {
    *output++ = *first;
    first = std::upper_bound(first, last, *first);
  }
  return output;
}

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