LeetCode-in-All
20. Valid Parentheses
Easy
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.
Example 1:
Input: s = “()”
Output: true
Example 2:
Input: s = “()[]{}”
Output: true
Example 3:
Input: s = “(]”
Output: false
Example 4:
Input: s = “([)]”
Output: false
Example 5:
Input: s = “{[]}”
Output: true
Constraints:
1 <= s.length <= 104sconsists of parentheses only'()[]{}'.
Solution
#include <stdbool.h>
#include <string.h>
#include <string.h>
bool isValid(char *s) {
int n = strlen(s);
if (n % 2 != 0) return false; // Check for odd length
int i = 0;
while (i < n - 1) {
if ((s[i] == '(' && s[i + 1] == ')') ||
(s[i] == '{' && s[i + 1] == '}') ||
(s[i] == '[' && s[i + 1] == ']')) {
// Remove matched parentheses
memmove(&s[i], &s[i + 2], n - i - 1);
n -= 2;
s[n] = '\0';
if (i >= 1) i--;
} else {
i++;
}
}
return n == 0;
}