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| 1 | +class Solution { |
| 2 | +private: |
| 3 | + inline string Check(string &s, int widths[]) |
| 4 | + { |
| 5 | + widths[1] += widths[0] ; |
| 6 | + widths[2] += widths[1] ; |
| 7 | + widths[3] = s.length() - widths[2] ; |
| 8 | + |
| 9 | + if (widths[3] < 1 || widths[3] > 3 ) |
| 10 | + return "" ; |
| 11 | + |
| 12 | + widths[3] = s.length() ; |
| 13 | + |
| 14 | + for (int seg = 0; seg < 4; ++seg) |
| 15 | + { |
| 16 | + int num = 0 ; |
| 17 | + for (int i = (seg == 0? 0: widths[seg-1]); i < widths[seg]; ++i) |
| 18 | + { |
| 19 | + num *= 10 ; |
| 20 | + num += s[i] - '0' ; |
| 21 | + } |
| 22 | + if (num > 255) |
| 23 | + return "" ; |
| 24 | + |
| 25 | + int w = widths[seg] - (seg == 0? 0: widths[seg-1]) ; |
| 26 | + if (w == 3 && num < 100) |
| 27 | + return "" ; |
| 28 | + if (w == 2 && num < 10) |
| 29 | + return "" ; |
| 30 | + } |
| 31 | + string res = s ; |
| 32 | + for (int i = 2; i >= 0; --i) |
| 33 | + res.insert(widths[i], ".") ; |
| 34 | + |
| 35 | + return res ; |
| 36 | + } |
| 37 | +public: |
| 38 | + vector<string> restoreIpAddresses(string s) { |
| 39 | + int widths[4] ; |
| 40 | + vector<string> res ; |
| 41 | + for (int i = 0; i < 27; ++i) |
| 42 | + { |
| 43 | + widths[0] = 1 + i%3 ; |
| 44 | + widths[1] = 1 + i/3%3 ; |
| 45 | + widths[2] = 1 + i/9 ; |
| 46 | + |
| 47 | + string tmp = Check(s, widths) ; |
| 48 | + if (tmp.size() != 0) |
| 49 | + res.push_back(tmp) ; |
| 50 | + } |
| 51 | + |
| 52 | + return res; |
| 53 | + } |
| 54 | +}; |
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