LeetCode20-有效的括号

LeetCode20-有效的括号

使用栈

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public boolean isValid(String s) {
Stack<Character> stack = new Stack<>();

for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (c == '(' || c == '[' || c == '{') {
stack.push(c);
} else {
if (stack.isEmpty()) {
return false;
} else {
char topChar = stack.pop();
if (c == ')' && topChar != '(') {
return false;
}
if (c == ']' && topChar != '[') {
return false;
}
if (c == '}' && topChar != '{') {
return false;
}
}
}
}

return stack.isEmpty();
}