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class Solution {
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 public:
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  int maxEnvelopes(vector<vector<int>> &envelopes) {
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    int n = envelopes.size();
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    sort(envelopes.begin(), envelopes.end(),
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         [](auto &l, auto &r) { return l[0] == r[0] ? l[1] > r[1] : l[0] < r[0]; });
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    int len = 0;
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    for (auto &cur : envelopes) {
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      if (len == 0 || envelopes[len - 1][1] < cur[1])
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        envelopes[len++] = cur;
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      else
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        *lower_bound(envelopes.begin(), envelopes.begin() + len, cur,
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                     [](auto &l, auto &r) { return l[1] < r[1]; }) = cur;
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    }
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    return len;
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  }
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};