题解 | #有效括号序列#
有效括号序列
https://www.nowcoder.com/practice/37548e94a270412c8b9fb85643c8ccc2
import java.util.*; public class Solution { /** * * @param s string字符串 * @return bool布尔型 */ public boolean isValid (String s) { // write code here Stack<Character> stack = new Stack<>(); for (int i = 0; i < s.length(); i++) { char cha = s.charAt(i); char pre ; switch (cha) { case '(': case '[': case '{': stack.push(cha); break; case ')': if (stack.isEmpty()) { return false; } pre = stack.pop(); if (pre != '(') { return false; } break; case ']': if (stack.isEmpty()) { return false; } pre = stack.pop(); if (pre != '[') { return false; } break; case '}': if (stack.isEmpty()) { return false; } pre = stack.pop(); if (pre != '{') { return false; } break; default: return false; } } if (stack.isEmpty()) { return true; } else { return false; } } }