[leetCode刷题笔记]385. Mini Parser

最新推荐文章于 2022-10-10 17:08:54 发布

原创最新推荐文章于 2022-10-10 17:08:54 发布 · 348 阅读

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本文介绍了一个用于处理NestedInteger对象的解决方案，该对象可以包含整数或嵌套的NestedInteger列表。通过实现一个名为deserialize的方法，将字符串转换为NestedInteger对象，支持解析包含嵌套列表和整数的JSON风格字符串。

/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * public interface NestedInteger {
 *     // Constructor initializes an empty nested list.
 *     public NestedInteger();
 *
 *     // Constructor initializes a single integer.
 *     public NestedInteger(int value);
 *
 *     // @return true if this NestedInteger holds a single integer, rather than a nested list.
 *     public boolean isInteger();
 *
 *     // @return the single integer that this NestedInteger holds, if it holds a single integer
 *     // Return null if this NestedInteger holds a nested list
 *     public Integer getInteger();
 *
 *     // Set this NestedInteger to hold a single integer.
 *     public void setInteger(int value);
 *
 *     // Set this NestedInteger to hold a nested list and adds a nested integer to it.
 *     public void add(NestedInteger ni);
 *
 *     // @return the nested list that this NestedInteger holds, if it holds a nested list
 *     // Return null if this NestedInteger holds a single integer
 *     public List<NestedInteger> getList();
 * }
 */
public class Solution {
    public NestedInteger deserialize(String s) {
        if (s.isEmpty()) {
            return null;
        }
        if (s.charAt(0) != '[') {
            return new NestedInteger(Integer.valueOf(s));
        }
        Stack<NestedInteger> stack = new Stack<NestedInteger>();
        NestedInteger curr = null;
        int l = 0;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == '[') {
                if (curr != null) {
                    stack.push(curr);
                }
                curr = new NestedInteger();
                l = i + 1;
            }
            else if (s.charAt(i) == ']') {
                String val = s.substring(l , i);
                if (!val.isEmpty()) {
                    curr.add(new NestedInteger(Integer.valueOf(val)));
                }
                if (!stack.isEmpty()) {
                    NestedInteger pop = stack.pop();
                    pop.add(curr);
                     curr = pop;
                }
                l = i + 1;
            }
            else if (s.charAt(i) == ',') {
                if (s.charAt(i - 1) != ']') {
                    String num = s.substring(l, i);
                    curr.add(new NestedInteger(Integer.valueOf(num)));
                    
                }
                l = i + 1;
            } 
        }
        return curr;
    }
}