LeetCode p20 Valid Parentheses 题解
1.题目：
Given a string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, determine if the input string is valid.
The brackets must close in the correct order, “()” and “()[]{}” are all valid but “(]” and “([)]” are not.
题意：
判断一个字符串内的所有括号是否搭配得当。
2.解题思路:
使用栈匹配
3.代码
[title] [] [url] [link text]
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public class {
public boolean isValid(String s) {
Stack<Character> stack = new Stack<Character>();
String x = "([{";
String y = ")]}";
for (char a : s.toCharArray()) {
if (stack.size() != 0) {
int i = x.indexOf(stack.peek());
if (i < 0)
return false;
if (i == y.indexOf(a)) {
stack.pop();
} else {
stack.add(a);
}
} else {
stack.add(a);
}
}
return stack.size() == 0 ? true : false;
}
}
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4.一些总结：
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