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[leetcode-604-Design Compressed String Iterator]
Design and implement a data structure for a compressed string iterator. It should support the following operations: next
and hasNext
.
The given compressed string will be in the form of each letter followed by a positive integer representing the number of this letter existing in the original uncompressed string.
next()
- if the original string still has uncompressed characters, return the next letter; Otherwise return a white space.hasNext()
- Judge whether there is any letter needs to be uncompressed.
Note:
Please remember to RESET your class variables declared in StringIterator, as static/class variables are persisted across multiple test cases. Please see here for more details.
Example:
StringIterator iterator = new StringIterator("L1e2t1C1o1d1e1"); iterator.next(); // return ‘L‘ iterator.next(); // return ‘e‘ iterator.next(); // return ‘e‘ iterator.next(); // return ‘t‘ iterator.next(); // return ‘C‘ iterator.next(); // return ‘o‘ iterator.next(); // return ‘d‘ iterator.hasNext(); // return true iterator.next(); // return ‘e‘ iterator.hasNext(); // return false iterator.next(); // return ‘ ‘
思路:
需要注意的是,数字可能是大于10的也就是说不一定是一位数。。。
参考了大神的代码。。
class StringIterator { string a; size_t i = 0, c = 0; char ch; public: StringIterator(string a) { this->a = a; } char next() { if (c) return c--, ch; if (i >= a.size()) return ‘ ‘; ch = a[i++]; while (i < a.size() && isdigit(a[i])) c = c*10+a[i++]-‘0‘; c--; return ch; } bool hasNext() { return c || i < a.size(); } };
参考:
https://leetcode.com/maskray/
[leetcode-604-Design Compressed String Iterator]