C. Longest Regular Bracket Sequence
Time Limit: 20 Sec
Memory Limit: 256 MB
题目连接
http://codeforces.com/problemset/problem/5/C
Description
This is yet another problem dealing with regular bracket sequences.
We should remind you that a bracket sequence is called regular, if by inserting «+» and «1» into it we can get a correct mathematical expression. For example, sequences «(())()», «()» and «(()(()))» are regular, while «)(», «(()» and «(()))(» are not.
You are given a string of «(» and «)» characters. You are to find its longest substring that is a regular bracket sequence. You are to find the number of such substrings as well.
We should remind you that a bracket sequence is called regular, if by inserting «+» and «1» into it we can get a correct mathematical expression. For example, sequences «(())()», «()» and «(()(()))» are regular, while «)(», «(()» and «(()))(» are not.
You are given a string of «(» and «)» characters. You are to find its longest substring that is a regular bracket sequence. You are to find the number of such substrings as well.
Input
The first line of the input file contains a non-empty string, consisting of «(» and «)» characters. Its length does not exceed 106.
Output
Print the length of the longest substring that is a regular bracket sequence, and the number of such substrings. If there are no such substrings, write the only line containing "0 1".
Sample Input
)((())))(()())
Sample Output
6 2
HINT
题意
给你一个括号序列,让你找到最长的连续的合法括号序列
然后让你输出这个括号序列的长度是多少
这么长的括号序列一共有多少个
题解:
看到括号匹配,就用stack来弄就好了
然后我们再简单dp一下,表示以这个字符结尾的序列的长度是多少
然后跑一发就好了
代码
//qscqesze #include <cstdio> #include <cmath> #include <cstring> #include <ctime> #include <iostream> #include <algorithm> #include <set> #include <vector> #include <sstream> #include <queue> #include <typeinfo> #include <fstream> #include <map> #include <stack> typedef long long ll; using namespace std; //freopen("D.in","r",stdin); //freopen("D.out","w",stdout); #define sspeed ios_base::sync_with_stdio(0);cin.tie(0) #define maxn 2000001 #define mod 10007 #define eps 1e-9 int Num; char CH[20]; //const int inf=0x7fffffff; //нчоч╢С const int inf=0x3f3f3f3f; /* inline void P(int x) { Num=0;if(!x){putchar('0');puts("");return;} while(x>0)CH[++Num]=x%10,x/=10; while(Num)putchar(CH[Num--]+48); puts(""); } */ inline ll read() { int x=0,f=1;char ch=getchar(); while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();} while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();} return x*f; } inline void P(int x) { Num=0;if(!x){putchar('0');puts("");return;} while(x>0)CH[++Num]=x%10,x/=10; while(Num)putchar(CH[Num--]+48); puts(""); } //************************************************************************************** string s; stack<int> k; int dp[maxn]; int main() { cin>>s; for(int i=0;i<s.size();i++) { if(s[i]=='(') k.push(i); else { if(!k.empty()) { dp[i]=i-k.top()+1; if(k.top()>0) dp[i]+=dp[k.top()-1]; k.pop(); } } } int ans1=0,ans2=1; for(int i=0;i<s.size();i++) { if(dp[i]>ans1) { ans1=dp[i]; ans2=1; } else if(dp[i]==ans1) ans2++; } if(ans1==0) printf("0 1 "); else cout<<ans1<<" "<<ans2<<endl; }