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class Solution {
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 public:
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  bool validMountainArray(vector<int> &arr) {
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    int flag = 1;
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    if ((arr.size() <= 2) || (arr[1] <= arr[0])) return false;
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    for (int i = 1; i < arr.size(); i++) {
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      if (flag) {
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        if (arr[i] > arr[i - 1]) continue;
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        i--;
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        flag = 0;
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      } else {
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        if (arr[i] < arr[i - 1]) continue;
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        return false;
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      }
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    }
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    if (flag) return false;
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    return true;
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  }
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};
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****