题目描述
思路
思路：
- 碰到数字：压入数字栈，注意多位数的情况
- 碰到字母：直接拼接到res
- 遇到[：将num和res分别压入栈
- 遇到]：开始处理栈顶元素
方法一：
class Solution {
public String decodeString(String s) {
int num = 0;
StringBuilder res = new StringBuilder();
Deque<String> DigStack = new ArrayDeque<>();
Deque<Integer> NumStack = new ArrayDeque<>();
for (char c : s.toCharArray()) {
if (c >= '0' && c <= '9') {
num = num * 10 + (c - '0');
} else if (c == '[') {
NumStack.push(num);
DigStack.push(res.toString());
res.delete(0, res.length());
num = 0;
} else if (c == ']') {
String item = res.toString();
int times = NumStack.pop();
for (int i = 0; i < times - 1; i ++) {
res.append(item);
}
res.insert(0, DigStack.pop());
} else{
res.append(c);
}
}
return res.toString();
}
}