标签：tip lin size mic span word file ++i desc
Description
We give the following inductive definition of 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
题解
区间dp，和1141那道题做法很像
1 #include<cstdio> 2 #include<algorithm> 3 #include<cstring> 4 using namespace std; 5 int dp[110][110]; 6 char str[110]; 7 bool ok(int x,int y) 8 { 9 if(str[x]==‘(‘&&str[y]==‘)‘)return true; 10 if(str[x]==‘[‘&&str[y]==‘]‘)return true; 11 return false; 12 } 13 int main() 14 { 15 while(1) 16 { 17 scanf("%s",str+1); 18 if(str[1]==‘e‘)break; 19 int l=strlen(str+1); 20 for(int k=2 ; k<=l ; ++k ) 21 for(int i=1,j=i+k-1 ; j<=l ; ++i,j=i+k-1) 22 { 23 dp[i][j]=0; 24 if(ok(i,j))dp[i][j]=dp[i+1][j-1]+2; 25 for(int p=i ; p<j ; ++p ) 26 dp[i][j]=max(dp[i][j],dp[i][p]+dp[p+1][j]); 27 } 28 printf("%d\n",dp[1][l]); 29 } 30 return 0; 31 }
标签：tip lin size mic span word file ++i desc
原文地址：http://www.cnblogs.com/fujudge/p/7523087.html
