leetcode

0 /**

1 * // This is the interface that allows for creating nested lists.

2 * // You should not implement it, or speculate about its implementation

3 * class NestedInteger {

4 * public:

5 * // Constructor initializes an empty nested list.

6 * NestedInteger();

7 *

8 * // Constructor initializes a single integer.

9 * NestedInteger(int value);

10 *

11 * // Return true if this NestedInteger holds a single integer, rather than a nested list.

12 * bool isInteger() const;

13 *

14 * // Return the single integer that this NestedInteger holds, if it holds a single integer

15 * // The result is undefined if this NestedInteger holds a nested list

16 * int getInteger() const;

17 *

18 * // Set this NestedInteger to hold a single integer.

19 * void setInteger(int value);

20 *

21 * // Set this NestedInteger to hold a nested list and adds a nested integer to it.

22 * void add(const NestedInteger &ni);

23 *

24 * // Return the nested list that this NestedInteger holds, if it holds a nested list

25 * // The result is undefined if this NestedInteger holds a single integer

26 * const vector<NestedInteger> &getList() const;

27 * };

28 */

29 class Solution {

30 public:

31 NestedInteger deserialize(const string &s) const {

32 if (s[0] != '[') return NestedInteger(stoi(s));

33

34 stack<NestedInteger> st;

35 const int n = size(s);

36

37 for (int i = 0; i < n - 1; i++) {

38 if (s[i] == ',') continue;

39

40 if (s[i] == '[')

41 st.push({});

42 else if (s[i] == ']') {

43 const auto top = st.top();

44 st.pop();

45 st.top().add(top);

46 } else {

47 const int start = i;

48 while (i < n && s[i] != '[' && s[i] != ']' && s[i] != ',')

49 i++;

50 st.top().add(stoi(s.substr(start, i - start)));

51 i--;

52 }

53 }

54

55 return st.top();

56 }

57 };