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class Solution {
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 public:
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  bool isSelfCrossing(vector<int> &distance) {
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    if (distance.size() <= 3) return false; // only can have intersection with more than 4 lines
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    distance.insert(distance.begin(),
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                    0); // for the edge case: line i intersect with line i-4 at (0, 0)
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    for (int i = 3; i < distance.size(); i++) {
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      // check line i-3
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      if (distance[i - 2] <= distance[i] && distance[i - 1] <= distance[i - 3]) return true;
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      // check line i-5
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      if (i >= 5) {
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        if (distance[i - 1] <= distance[i - 3] &&
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            distance[i - 1] >= distance[i - 3] - distance[i - 5] &&
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            distance[i - 2] >= distance[i - 4] && distance[i - 2] <= distance[i - 4] + distance[i])
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          return true;
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      }
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    }
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    return false;
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  }
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};