poj 2955 区间dp

题意：求最大括号匹配

链接：点我

区间dp水题，但也是很经典，区间dp都是由此延伸出来的，越是基础题越是需要勤加练习

Sample Input

((()))

()()()

([]])

)[)(

([][][)

end

Sample Output

6

6

4

0

6

 

2015-07-19：专题复习纪念

 1 #include<cstdio>

 2 #include<iostream>

 3 #include<algorithm>

 4 #include<cstring>

 5 #include<cmath>

 6 #include<queue>

 7 #include<map>

 8 using namespace std;

 9 #define MOD 1000000007

10 const int INF=0x3f3f3f3f;

11 const double eps=1e-5;

12 typedef long long ll;

13 #define cl(a) memset(a,0,sizeof(a))

14 #define ts printf("*****\n");

15 const int MAXN=1005;

16 int n,m,tt;

17 char s[MAXN];

18 int dp[MAXN][MAXN];

19 int flag[MAXN][MAXN];

20 int main()

21 {

22     int i,j,k;

23     #ifndef ONLINE_JUDGE

24     freopen("1.in","r",stdin);

25     #endif

26     while(gets(s))

27     {

28         if(s[0]=='e')   break;

29         int len=strlen(s);

30         for(i=0;i<len;i++)  dp[i][i]=0;

31         for(int d=1;d<len;d++)

32         {

33             for(i=0;i+d<len;i++)

34             {

35                 j=i+d;

36                 dp[i][j]=-999999;

37                 if((s[i]=='('&&s[j]==')')||(s[i]=='['&&s[j]==']'))

38                 {

39                     dp[i][j]=dp[i+1][j-1]+1;

40                 }

41                 for(k=i;k<j;k++)

42                 {

43                     if(dp[i][j]<dp[i][k]+dp[k+1][j])

44                     {

45                         dp[i][j]=dp[i][k]+dp[k+1][j];

46                     }

47                 }

48             }

49         }

50         printf("%d\n",dp[0][len-1]*2);

51     }

52 }

View Code

 

 

 1 #include<cstdio>

 2 #include<iostream>

 3 #include<algorithm>

 4 #include<cstring>

 5 #include<cmath>

 6 #include<queue>

 7 #include<map>

 8 using namespace std;

 9 #define MOD 1000000007

10 const int INF=0x3f3f3f3f;

11 const double eps=1e-5;

12 typedef long long ll;

13 #define cl(a) memset(a,0,sizeof(a))

14 #define ts printf("*****\n");

15 const int MAXN=1005;

16 int n,m,tt;

17 int dp[MAXN][MAXN];

18 int main()

19 {

20     int i,j,k;

21     #ifndef ONLINE_JUDGE

22     freopen("1.in","r",stdin);

23     #endif

24     char s[MAXN];

25     while(scanf("%s",s)!=EOF)

26     {

27         if(s[0]=='e')   break;

28         int len=strlen(s);

29         cl(dp);

30         for(int d=1;d<len;d++)

31         {

32             for(i=0;d+i<len;i++)

33             {

34                 j=d+i;

35                 if((s[i]=='('&&s[j]==')')||(s[i]=='['&&s[j]==']'))  dp[i][j]=dp[i+1][j-1]+2;

36                 for(k=i;k<=j;k++)

37                 {

38                     dp[i][j]=max(dp[i][j],dp[i][k]+dp[k+1][j]);

39                 }

40             }

41         }

42         printf("%d\n",dp[0][len-1]);

43     }

44 }