标签：ica algorithm return 区间dp where single input reg printf
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
题意给你一个只含()[]的字符串，问你最多能配成对的有多少个和字符。
区间dp的入门题。整理下思路dp[i][j]表示区间i~j之间最大的匹配字符数。
if ((s[i]==‘(‘&&s[j]==‘)‘)||(s[i]==‘[‘&&s[j]==‘]‘)) ————>dp[i][j]=dp[i+1][j-1]+2; 懂吧
代码如下：
1 #include <cstdio> 2 #include <algorithm> 3 #include <cstring> 4 #include <cmath> 5 #include <iostream> 6 7 using namespace std; 8 char s[110]; 9 int dp[110][110]; 10 int main() 11 { 12 //freopen("de.txt","r",stdin); 13 while (~scanf("%s",&s)) 14 { 15 if (s[0]==‘e‘) 16 break ; 17 memset(dp,0,sizeof dp); 18 int len=strlen(s); 19 for (int k=1;k<len;++k) 20 { 21 for (int i=0,j=k;j<len;++i,++j) 22 { 23 if ((s[i]==‘(‘&&s[j]==‘)‘)||(s[i]==‘[‘&&s[j]==‘]‘)) 24 dp[i][j]=dp[i+1][j-1]+2; 25 for (int x=i;x<j;x++) 26 dp[i][j]=max(dp[i][j],dp[i][x]+dp[x+1][j]); 27 } 28 } 29 printf("%d\n",dp[0][len-1]); 30 } 31 return 0; 32 }
标签：ica algorithm return 区间dp where single input reg printf
原文地址：http://www.cnblogs.com/agenthtb/p/6034573.html
