int main(void) {
char s[11];
scanf("%s", s);
bool r = nestParen (s, 0, 0);
printf("%d\n", (int)r);
return EXIT_SUCCESS;
}
bool nestParen (char x[], int i, int z) {
if (x[i] == 0 || z < 0) {
return z == 0;
}
if (x[i] == '(') {
z++;
} else if (x[i] == ')') {
z--;
}
return nestParen(x, i+1, z);
}
// Given a string, return true if it is a nesting of zero or more pairs of parenthesis, like "(())" or "((()))". Suggestion: check the first and last chars, and then recur on what's inside them.
bool nestParen( string str )
{
if( str.empty() )
return true;
if( str.length() >= 2 )
return ( str.at( 0 ) == '(' && str.at( str.length() - 1 ) == ')' ) &&
nestParen( str.substr( 1, str.length() - 2 ) );
return false;
}