hdu 1503 记忆化搜索＋递归输出＋标记前驱

来源：互联网发布：绘图设计软件编辑：程序博客网时间：2024/06/05 15:24

速度比stl版本快很多，０秒过．．．

#include <iostream>#include <cstring>#include <algorithm>#include <cstdio>#include <string>#define MAX 107using namespace std;int dp[MAX][MAX];//string s[MAX][MAX];struct Pre{    int x , y;    char c;}pre[MAX][MAX];char s1[MAX] , s2[MAX];void dfs ( int i , int j ){    if ( dp[i][j] != -1 )  return;    if ( i== 0 && j== 0 )    {        dp[i][j] = 0;        pre[i][j].x = -1;        pre[i][j].y = -1;        pre[i][j].c = 0;        return;    }    if ( i >= 1 && j >= 1 && s1[i] == s2[j] )    {        if ( dp[i-1][j-1] == -1 ) dfs (  i-1 , j-1 );        if ( dp[i][j] != -1 && dp[i][j] > dp[i-1][j-1] + 1 )            dp[i][j] =  dp[i-1][j-1]+1 ,            pre[i][j].x=i-1 , pre[i][j].y=j-1,            pre[i][j].c = s1[i];        else if ( dp[i][j] == -1 )             dp[i][j] = dp[i-1][j-1],            pre[i][j].x=i-1 , pre[i][j].y=j-1;            pre[i][j].c = s1[i];    }    if ( i>=1 && dp[i-1][j] == -1 ) dfs ( i-1 , j );    if ( j>=1 && dp[i][j-1] == -1 ) dfs ( i , j-1 );    if ( i>=1 && ( dp[i][j] > dp[i-1][j]+1||dp[i][j] == -1 ) )        dp[i][j] = dp[i-1][j]+1,        pre[i][j].x = i-1 , pre[i][j].y = j,        pre[i][j].c = s1[i];    if ( j>=1 && ( dp[i][j] > dp[i][j-1]+1||dp[i][j] == -1 ) )        dp[i][j] = dp[i][j-1]+1 ,        pre[i][j].x = i , pre[i][j].y = j-1,        pre[i][j].c = s2[j];}void print ( int x , int y ){    if ( pre[x][y].x == -1 ) return;    print ( pre[x][y].x , pre[x][y].y );    printf ( "%c" , pre[x][y].c );}   int main ( ){    while ( ~scanf ( "%s" , s1+1 ) )    {        scanf ( "%s" , s2+1 );        int len1 = strlen (s1+1);        int len2 = strlen (s2+1);        memset ( dp , -1 , sizeof ( dp ) );        dfs ( len1 , len2 );        print ( len1 , len2 );        puts ( "" );    }}

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