LeetCode-20 Valid Parentheses

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

An input string is valid if:

1. Open brackets must be closed by the same type of brackets.
2. Open brackets must be closed in the correct order.

Note that an empty string is also considered valid.

Example 1:

Input: "()"
Output: true

Example 2:

Input: "()[]{}"
Output: true

Example 3:

Input: "(]"
Output: false

Example 4:

Input: "([)]"
Output: false

Example 5:

Input: "{[]}"
Output: true

  很簡單的一道括號匹配的題，用一個棧就可以實現了，沒什麼難度。

bool isValid(char* s) {
    int i,top;
    char stack[10000];
    i = 0;
    top = -1;
    while(s[i] != '\0')
    {
        switch(s[i])
        {
            case '[':
                top++;
                stack[top] = '[';
                break;
            case '{':
                top++;
                stack[top] = '{';
                break;
            case '(':
                top++;
                stack[top] = '(';
                break;
            case ']':
                if(top == -1)
                    return false;
                if(stack[top] != '[')
                    return false;
                top--;
                break;
            case '}':
                if(top == -1)
                    return false;
                if(stack[top] != '{')
                    return false;
                top--;
                break;
            case ')':
                if(top == -1)
                    return false;
                if(stack[top] != '(')
                    return false;
                top--;
                break;
        }
        i++; 
    }
    if(top != -1)
        return false;
    return true;
}