ZOJ 1463 Brackets Sequence

区间DP，刘汝佳黑书p113例题

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>

using namespace std;

const int MAXN = 210;
const int INF = 1 << 30;

char str[MAXN];
int dp[MAXN][MAXN];
int path[MAXN][MAXN];
bool vis[MAXN][MAXN];
int len;

inline bool check( char a, char b )
{
    return (a == '(' && b == ')') || ( a == '[' && b == ']' );
}

void PrintPath( int i, int j )
{
    if ( i > j ) return;
    if ( i == j )
    {
        if ( str[i] == '[' || str[i] == ']' )
            printf( "[]" );
        else printf( "()" );
        return;
    }
    if ( path[i][j] == -1 )
    {
        putchar( str[i] );
        PrintPath( i + 1, j - 1 );
        putchar( str[j] );
    }
    else
    {
        PrintPath( i, path[i][j] );
        PrintPath( path[i][j] + 1, j );
    }
}

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

    for ( int p = 1; p < len; ++p )
    for ( int i = 1; i <= len - p; ++i )
    {
        int j = i + p;
        dp[i][j] = INF;
        if ( check( str[i], str[j] ) )
        {
            if ( dp[i + 1][j - 1] < dp[i][j] )
            {
                dp[i][j] = dp[i + 1][j - 1];
                path[i][j] = -1;
            }
        }

        for ( int k = i; k < j; ++k )
        {
            if ( dp[i][k] + dp[k + 1][j] < dp[i][j] )
            {
                dp[i][j] = dp[i][k] + dp[k + 1][j];
                path[i][j] = k;
            }
        }
    }
    return;
}

int main()
{
    int T;
    bool flag = false;
    scanf( "%d", &T );
    getchar();
    while ( T-- )
    {
        getchar();
        gets( &str[1] );
        len = strlen( &str[1] );
        DP();
        if ( flag ) putchar('\n');
        PrintPath( 1, len );
        putchar('\n');
        flag = true;
    }
    return 0;
}