ZOJ 1463 Brackets Sequence

区间DP，刘汝佳黑书p113例题

 1 #include <cstdio>

 2 #include <cstring>

 3 #include <cstdlib>

 4 #include <algorithm>

 5 

 6 using namespace std;

 7 

 8 const int MAXN = 210;

 9 const int INF = 1 << 30;

10 

11 char str[MAXN];

12 int dp[MAXN][MAXN];

13 int path[MAXN][MAXN];

14 bool vis[MAXN][MAXN];

15 int len;

16 

17 inline bool check( char a, char b )

18 {

19     return (a == '(' && b == ')') || ( a == '[' && b == ']' );

20 }

21 

22 void PrintPath( int i, int j )

23 {

24     if ( i > j ) return;

25     if ( i == j )

26     {

27         if ( str[i] == '[' || str[i] == ']' )

28             printf( "[]" );

29         else printf( "()" );

30         return;

31     }

32     if ( path[i][j] == -1 )

33     {

34         putchar( str[i] );

35         PrintPath( i + 1, j - 1 );

36         putchar( str[j] );

37     }

38     else

39     {

40         PrintPath( i, path[i][j] );

41         PrintPath( path[i][j] + 1, j );

42     }

43 }

44 

45 void DP()

46 {

47     for ( int i = 1; i <= len; ++i ) dp[i][i - 1] = 0;

48     for ( int i = 1; i <= len; ++i ) dp[i][i] = 1;

49 

50     for ( int p = 1; p < len; ++p )

51     for ( int i = 1; i <= len - p; ++i )

52     {

53         int j = i + p;

54         dp[i][j] = INF;

55         if ( check( str[i], str[j] ) )

56         {

57             if ( dp[i + 1][j - 1] < dp[i][j] )

58             {

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

60                 path[i][j] = -1;

61             }

62         }

63 

64         for ( int k = i; k < j; ++k )

65         {

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

67             {

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

69                 path[i][j] = k;

70             }

71         }

72     }

73     return;

74 }

75 

76 int main()

77 {

78     int T;

79     bool flag = false;

80     scanf( "%d", &T );

81     getchar();

82     while ( T-- )

83     {

84         getchar();

85         gets( &str[1] );

86         len = strlen( &str[1] );

87         DP();

88         if ( flag ) putchar('\n');

89         PrintPath( 1, len );

90         putchar('\n');

91         flag = true;

92     }

93     return 0;

94 }