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class Solution {
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 public:
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  int maxValueAfterReverse(vector<int> &nums) {
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    int original = 0;
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    for (int i = 0; i < nums.size() - 1; ++i) {
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      original += abs(nums[i] - nums[i + 1]);
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    }
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    int ans = original;
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    int a1 = INT_MAX;
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    int a2 = INT_MAX;
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    int a3 = INT_MIN;
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    int a4 = INT_MIN;
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    int n = nums.size();
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    for (int i = n - 2; i >= 1; --i) {
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      int old = nums[i - 1];
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      int now = nums[i];
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      if (i != n - 2) {
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        int y1 = (nums[i - 1] + nums[i]) - abs(old - now) - a1 + original;
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        int y2 = (nums[i - 1] - nums[i]) - abs(old - now) - a2 + original;
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        int y3 = (nums[i] - nums[i - 1]) - abs(old - now) + a3 + original;
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        int y4 = -(nums[i - 1] + nums[i]) - abs(old - now) + a4 + original;
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        ans = max(max(y4, max(y1, max(y2, y3))), ans);
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      }
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      a1 = min(a1, nums[i] + nums[i + 1] + abs(nums[i] - nums[i + 1]));
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      a2 = min(a2, nums[i] - nums[i + 1] + abs(nums[i] - nums[i + 1]));
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      a3 = max(a3, nums[i] - nums[i + 1] - abs(nums[i] - nums[i + 1]));
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      a4 = max(a4, nums[i] + nums[i + 1] - abs(nums[i] - nums[i + 1]));
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      ans = max(ans, -abs(old - now) + abs(old - nums[nums.size() - 1] + original));
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    }
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    for (int i = 1; i < n - 1; ++i) {
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      ans = max(ans, -abs(nums[i] - nums[i + 1]) + abs(nums[0] - nums[i + 1]) + original);
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    }
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    return ans;
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  }