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public boolean isValid(String s) {
Java · leetcode · type the snippet below to practice
def fib(n):
a, b = 0, 1
for _ in range(n):
a, b = b, a + b
return a
about this snippet
This is the validparens snippet in Java — a classic LeetCode interview problem. Type it through to build the muscle memory you need to write it under interview pressure. DeveloperType scores you on net WPM and accuracy and only counts runs above 95% accuracy on the leaderboard, so practice rewards precision, not speed alone.
view source (11 lines)
public boolean isValid(String s) {
Deque<Character> stack = new ArrayDeque<>();
for (char c : s.toCharArray()) {
if (c == '(') stack.push(')');
else if (c == '[') stack.push(']');
else if (c == '{') stack.push('}');
else if (stack.isEmpty() || stack.pop() != c) return false;
}
return stack.isEmpty();
}
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