Zoj1717 poj2030 the secret number

A really annoying DP. If you use DFS to do it, it's decisive. tle...

DP [x] [Y] indicates the longest string ending with the (x, y) character, it is known that the State can only be obtained from (x-1, Y), (X, Y-1.

/******************************************************************************* # Author : Neo Fung # Email : neosfung@gmail.com # Last modified: 2012-02-23 20:17 # Filename: ZOJ1717 POJ2030 The Secret Number.cpp # Description :  ******************************************************************************/#ifdef _MSC_VER#define DEBUG#define _CRT_SECURE_NO_DEPRECATE#endif#include <fstream>#include <stdio.h>#include <iostream>#include <string.h>#include <string>#include <limits.h>#include <algorithm>#include <math.h>#include <numeric>#include <functional>#include <ctype.h>#define MAX 80using namespace std;int mat[MAX][MAX];char dp[MAX][MAX][2*MAX];bool cmp(const char *lhs,const char *rhs){  const int llen=strlen(lhs),rlen=strlen(rhs);  if(llen != rlen)    return llen<rlen;  else    for(int i=0;i<llen;++i)      if(lhs[i]!=rhs[i])        return lhs[i]<rhs[i];  return false;}int main(void){#ifdef DEBUG    freopen("../stdin.txt","r",stdin);  freopen("../stdout.txt","w",stdout); #endif    int n,m;char temp,ans[2*MAX];  while(scanf("%d%d",&m,&n) &&(n||m))  {memset(mat,-1,sizeof(mat));    memset(dp,'\0',sizeof(dp));    memset(ans,'\0',sizeof(ans));for(int i=1;i<=n;++i)    {      getchar();for(int j=1;j<=m;++j){scanf("%c",&temp);if(isdigit(temp))mat[i][j]=temp-'0';elsemat[i][j]=-1;}    }for(int i=1;i<=n;++i)    {for(int j=1;j<=m;++j)        if(mat[i][j]>-1)        {          int a=strlen(dp[i-1][j]),b=strlen(dp[i][j-1]);          if(a&&b)          {            if(cmp(dp[i-1][j],dp[i][j-1]))            {              strcpy(dp[i][j],dp[i][j-1]);              dp[i][j][b++]=mat[i][j]+'0';              dp[i][j][b]='\0';            }            else            {              strcpy(dp[i][j],dp[i-1][j]);              dp[i][j][a++]=mat[i][j]+'0';              dp[i][j][a]='\0';            }          }          else if(a)          {            strcpy(dp[i][j],dp[i-1][j]);            dp[i][j][a++]=mat[i][j]+'0';            dp[i][j][a]='\0';          }          else if(b)          {            strcpy(dp[i][j],dp[i][j-1]);            dp[i][j][b++]=mat[i][j]+'0';            dp[i][j][b]='\0';          }          else if(mat[i][j]>0)          {            dp[i][j][0]=mat[i][j]+'0';          }          if(cmp(ans,dp[i][j]))            strcpy(ans,dp[i][j]);        }    }printf("%s\n",ans);  }  return 0;}