练习第18天

题目链接：https://leetcode.cn/problems/valid-parentheses/ 视频讲解：https://www.bilibili.com/video/BV1AF411w78g

char pairs(char a) { if (a == '}') return '{'; if (a == ']') return '['; if (a == ')') return '('; return 0; } bool isValid(char* s) { int n = strlen(s); if (n % 2 == 1) { return false; } int stk[n + 1], top = 0; for (int i = 0; i < n; i++) { char ch = pairs(s[i]); if (ch) { if (top == 0 || stk[top - 1] != ch) { return false; } top--; } else { stk[top++] = s[i]; } } return top == 0; }