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class Solution {
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 public:
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  int maxRepOpt1(string text) {
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    vector<pair<int, int>> intervals[26];
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    // a: [st, ed], .....
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    for (int i = 0; i < text.size();) {
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      int st = i, ed = i;
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      while (i < text.size() && text[i] == text[st]) {
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        ed = i;
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        i++;
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      }
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      intervals[text[st] - 'a'].push_back({st, ed});
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    }
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    int ans = 0;
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    for (int i = 0; i < 26; i++) {
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      for (int j = 0; j < intervals[i].size(); j++) {
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        // 单个的最大值
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        int len1 = intervals[i][j].second - intervals[i][j].first + 1;
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        if (intervals[i].size() > 1) len1++;
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        ans = max(ans, len1);
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        // 合并
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        // [1, 2] [4, 6]
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        if (j + 1 < intervals[i].size() &&
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            intervals[i][j].second + 2 == intervals[i][j + 1].first) {
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          int len2 = intervals[i][j].second - intervals[i][j].first + 1 +
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                     intervals[i][j + 1].second - intervals[i][j + 1].first + 1;
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          if (intervals[i].size() > 2) { // 一定有一个愿意牺牲
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            len2++;
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          }
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          ans = max(ans, len2);
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        }
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      }
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    }
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    return ans;
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  }
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};
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/**
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abababababac
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*/