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class Solution {
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 public:
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  int sumSubseqWidths(vector<int> &nums) {
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    vector<long long> pow(nums.size());
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    pow[0] = 1;
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    for (int i = 1; i < nums.size(); i++) {
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      pow[i] = pow[i - 1] * 2 % 1000000007;
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    }
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    sort(nums.begin(), nums.end());
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    long long ans = 0;
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    for (int i = 0; i < nums.size(); i++) {
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      ans = (ans + pow[i] * nums[i]) % 1000000007;
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      ans = (ans - pow[nums.size() - i - 1] * (long long)nums[i]) % 1000000007;
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    }
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    return ans;
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  }
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};