leetcode-cpp/0862.cpp at main · s4nj1th/leetcode-cpp · GitHub

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class Solution {
public:
  int shortestSubarray(vector<int> &nums, int targetSum) {
    int n = nums.size();

    vector<long long> prefixSums(n + 1, 0);

    for (int i = 1; i <= n; i++) {
      prefixSums[i] = prefixSums[i - 1] + nums[i - 1];
    }

    deque<int> candidateIndices;

    int shortestSubarrayLength = INT_MAX;

    for (int i = 0; i <= n; i++) {
      while (!candidateIndices.empty() &&
             prefixSums[i] - prefixSums[candidateIndices.front()] >=
                 targetSum) {
        shortestSubarrayLength =
            min(shortestSubarrayLength, i - candidateIndices.front());
        candidateIndices.pop_front();
      }

      while (!candidateIndices.empty() &&
             prefixSums[i] <= prefixSums[candidateIndices.back()]) {
        candidateIndices.pop_back();
      }

      candidateIndices.push_back(i);
    }

    return shortestSubarrayLength == INT_MAX ? -1 : shortestSubarrayLength;
  }
};