UVA 673 Parentheses Balance

題意就是判斷左右括号是否比對。用數組模拟棧，左括号就入棧，右括号遇到棧頂是對應的左括号，就将左括号出棧，否則就是NO，字元串結束後，若棧不為空，就NO。水過

#include <stdio.h>
#include <string.h>

int n;
char sb[205];
char stack[205];
int main()
{
	scanf("%d", &n);
	getchar();
	while (n --)
	{
		int i;
		memset(stack, 0, sizeof(stack));
		gets(sb);
		int t =0;
		int len = strlen(sb);
		for (i = 0; i < len; i ++)
		{
			if (sb[i] == '(' || sb[i] =='[')
			{
				stack[t] = sb[i];
				t ++;
			}
			if (sb[i] == ')')
			{
				if (stack[t - 1] == '(')
				{
					stack[t - 1] = '\0';
					t --;
				}
				else
				{
					stack[t] = sb[i];
					t ++;
				}
			}
			if (sb[i] == ']')
			{
				if (stack[t - 1] == '[')
				{
					stack[t - 1] = '\0';
					t --;
				}
				else
				{
					stack[t] = sb[i];
					t ++;
				}
			}
		}
		if (stack[0] == '\0')
			printf("Yes\n");
		else
			printf("No\n");
	}
	return 0;
}