贪心+stack Codeforces Beta Round #5 C. Longest Regular Bracket Sequence

/*
题意：求最长括号匹配的长度和它的个数
贪心+stack：用栈存放最近的左括号的位置，若是有右括号匹配，则记录它们的长度，更新最大值，可以在O (n)解决
详细解释：http://blog.csdn.net/taoxin52/article/details/26012167
*/
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <stack>
using namespace std; const int MAXN = 1e6 + ;
const int INF = 0x3f3f3f3f;
char s[MAXN];
int len[MAXN];
stack<int> S; int main(void) //Codeforces Beta Round #5 C. Longest Regular Bracket Sequence
{
// freopen ("C.in", "r", stdin); while (scanf ("%s", s) == )
{
while (!S.empty ()) S.pop ();
memset (len, , sizeof (len)); int mx = ; int cnt = ;
for (int i=; s[i]; ++i)
{
if (s[i] == '(') S.push (i);
else
{
if (!S.empty ())
{
int p = S.top (); S.pop ();
len[i] = (p > ? len[p-] : ) + (i - p + );
}
}
if (len[i] > mx) {mx = len[i]; cnt = ;}
else if (len[i] == mx) {cnt++;}
} if (mx == ) puts ("0 1");
else printf ("%d %d\n", mx, cnt);
} return ;
}