/
ValidParentheses.java
33 lines (32 loc) · 1.16 KB
/
ValidParentheses.java
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package com.thealgorithms.strings;
// Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine
// if the input string is valid. An input string is valid if: Open brackets must be closed by
// the same type of brackets. Open brackets must be closed in the correct order. Every close
// bracket has a corresponding open bracket of the same type.
public final class ValidParentheses {
private ValidParentheses() {
}
public static boolean isValid(String s) {
char[] stack = new char[s.length()];
int head = 0;
for (char c : s.toCharArray()) {
switch (c) {
case '{':
case '[':
case '(':
stack[head++] = c;
break;
case '}':
if (head == 0 || stack[--head] != '{') return false;
break;
case ')':
if (head == 0 || stack[--head] != '(') return false;
break;
case ']':
if (head == 0 || stack[--head] != '[') return false;
break;
}
}
return head == 0;
}
}