385. Mini Parser

最新推荐文章于 2024-09-25 07:32:56 发布

原创最新推荐文章于 2024-09-25 07:32:56 发布 · 230 阅读

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本文介绍了一种方法，用于将嵌套整数的字符串表示形式解析为嵌套整数对象。通过递归地处理字符串中的每一个元素，能够正确处理嵌套结构，并将每个整数或嵌套列表转换为相应的NestedInteger对象。

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * class NestedInteger {
 *   public:
 *     // Constructor initializes an empty nested list.
 *     NestedInteger();
 *
 *     // Constructor initializes a single integer.
 *     NestedInteger(int value);
 *
 *     // Return true if this NestedInteger holds a single integer, rather than a nested list.
 *     bool isInteger() const;
 *
 *     // Return the single integer that this NestedInteger holds, if it holds a single integer
 *     // The result is undefined if this NestedInteger holds a nested list
 *     int getInteger() const;
 *
 *     // Set this NestedInteger to hold a single integer.
 *     void setInteger(int value);
 *
 *     // Set this NestedInteger to hold a nested list and adds a nested integer to it.
 *     void add(const NestedInteger &ni);
 *
 *     // Return the nested list that this NestedInteger holds, if it holds a nested list
 *     // The result is undefined if this NestedInteger holds a single integer
 *     const vector<NestedInteger> &getList() const;
 * };
 */
class Solution {
public:
    NestedInteger deserialize(string s) {
        bool level=false;
        int len=s.size();
        if(s[0]=='[')
        {
            level=true;
            len-=2;
            s=s.substr(1,len);
        }
        
        NestedInteger obj;
        
        //for(int i=0;s[i]!='\0';i++)
        for(int i=0;i<len;i++)
        {
            if(isdigit(s[i])||s[i]=='-')
            {
                string tmp="";
                while(i<len&&(isdigit(s[i])||s[i]=='-'))
                {
                    tmp+=s[i++];
                }
                int item=atoi(tmp.c_str());
                NestedInteger ni(item);
                if(level)
                    obj.add(ni);
                else
                    obj.setInteger(item);
            }
            else if(s[i]=='[')
            {
                int cnt=1;
                int sta=i;
                i++;
                while(i<len&&cnt!=0)
                {
                    if(s[i]=='[')
                        cnt++;
                    else if(s[i]==']')
                        cnt--;
                    i++;
                }
                string tmp=s.substr(sta,i-sta);
                NestedInteger cur=deserialize(tmp);
                obj.add(cur);
            }
        }
        return obj;
    }
};
/*
"123"
"-11"
*/

update:

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * class NestedInteger {
 *   public:
 *     // Constructor initializes an empty nested list.
 *     NestedInteger();
 *
 *     // Constructor initializes a single integer.
 *     NestedInteger(int value);
 *
 *     // Return true if this NestedInteger holds a single integer, rather than a nested list.
 *     bool isInteger() const;
 *
 *     // Return the single integer that this NestedInteger holds, if it holds a single integer
 *     // The result is undefined if this NestedInteger holds a nested list
 *     int getInteger() const;
 *
 *     // Set this NestedInteger to hold a single integer.
 *     void setInteger(int value);
 *
 *     // Set this NestedInteger to hold a nested list and adds a nested integer to it.
 *     void add(const NestedInteger &ni);
 *
 *     // Return the nested list that this NestedInteger holds, if it holds a nested list
 *     // The result is undefined if this NestedInteger holds a single integer
 *     const vector<NestedInteger> &getList() const;
 * };
 */
class Solution {
public:
    NestedInteger deserialize(string s) {
        stack<NestedInteger* > st;
        if(s[0]!='[')
            return NestedInteger(stoi(s));
        
        int idx=0;   
        for(int i=0;s[i]!='\0';i++)
        {
            if(s[i]=='[')
            {
                st.push(new NestedInteger());
                idx=i+1;
            }
            else if(s[i]==']'||s[i]==',')
            {
                if(idx!=i)
                    st.top()->add(NestedInteger(stoi(s.substr(idx,i-idx))));
                if(s[i]==']')
                {
                    NestedInteger* cur=st.top();
                    st.pop();
                    if(!st.empty())
                        st.top()->add(*cur);
                    else
                        st.push(cur);
                }
                idx=i+1;
            }
        }
        return *st.top();
    }
};
/*
"123"
"-11"
*/