Brackets
| Time Limit: 1000MS |
|
Memory Limit: 65536K |
| Total Submissions: |
|
Accepted: |
Description
We give the following inductive definition of a “regular brackets” sequence:
the empty sequence is a regular brackets sequence,if
s is a regular brackets sequence, then (
s) and [
s] are regular brackets sequences, andif
a and
b are regular brackets sequences, then
ab is a regular brackets sequence.no other sequence is a regular brackets sequence
For instance, all of the following character sequences are regular brackets sequences:
(), [], (()), ()[], ()[()]
while the following character sequences are not:
(, ], )(, ([)], ([(]
Given a brackets sequence of characters a1a2 … an, your goal is to find the length of the longest regular brackets sequence that is a subsequence of s. That is, you wish to find the largest m such that for indices i1, i2, …, im where 1 ≤i1 < i2 < … < im ≤ n, ai1ai2 … aim is a regular brackets sequence.
Given the initial sequence ([([]])], the longest regular brackets subsequence is [([])].
Input
The input test file will contain multiple test cases. Each input test case consists of a single line containing only the characters (, ), [, and ]; each input test will have length between 1 and 100, inclusive. The end-of-file is marked by a line containing the word “end” and should not be processed.
Output
For each input case, the program should print the length of the longest possible regular brackets subsequence on a single line.
Sample Input
((()))
()()()
([]])
)[)(
([][][)
end
Sample Output
6
6
4
0
6
代码中详解!!!
AC代码如下:
#include
#include
#include
using namespace std; int dp[105][105]; char str[1005]; int main() { int i,j,o,t; while(cin>>str,str[0]!='e') { int l=strlen (str); for(i=0;i