题解 | #有效括号序列#

/**
 * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
 *
 *
 * @param s string字符串
 * @return bool布尔型
 */
char check(char pre) {
    if (pre == ')') return '(';
    else if (pre == ']') return '[';
    else if (pre == '}') return '{';
    return 0;
}
bool isValid(char* s ) {
    // write code here
    if (strlen(s) % 2 != 0)
        return 0;
    char* stack = (char*)malloc(sizeof(char) * strlen(s));
    int top = 0;

    int i = 0;
    for (i = 0; i < strlen(s); i++) {
        if (s[i] == '(' || s[i] == '[' || s[i] == '{') {
            stack[top] = s[i];
            top++;
        } else if (s[i] == ')' || s[i] == ']' || s[i] == '}') {
            top--;
            if (top < 0) {
                return 0;
            }
            if (stack[top] == check(s[i])) {
                stack[top] = '\0';
            } else {
                return 0;
            }
        }
    }
    if (strlen(stack) != 0) {
        return 0;
    } else {
        return 1;
    }
}