1287. Mars Canals

http://acm.timus.ru/problem.aspx?space=1&num=1287

我说Timus  你还能再水一些吗 递推 + 滚动数组

代码：

#include <iostream>

#include <cstdio>

#include <cstring>

#include <queue>

#include <algorithm>



#define LL long long



//#pragma comment(linker, "/STACK:1024000000,1024000000")

using namespace std;

const int N=1500;

char s[N][N];

struct node

{

    int ud,lr,k1,k2;

}ans[2][N];

int Snum,snum;

int Fmax4(int a,int b,int c,int d)

{

    if(a<b)

    a=b;

    if(a<c)

    a=c;

    if(a<d)

    a=d;

    return a;

}

int main()

{

    //freopen("data.txt","r",stdin);

    int n;

    while(scanf("%d",&n)!=EOF)

    {

        memset(s,0,sizeof(s));

        for(int i=1;i<=n;++i)

        {

            getchar();

            for(int j=1;j<=n;++j)

            {

                scanf("%c",&s[i][j]);

            }

        }

        Snum=0,snum=0;

        for(int i=1;i<=n;++i)

        {

            int l=i%2;

            int l1=(i-1)%2;

            for(int j=1;j<=n;++j)

            {

                ans[l][j].k1=1;

                ans[l][j].ud=1;

                ans[l][j].lr=1;

                if(s[i][j]==s[i-1][j])

                {

                    ans[l][j].ud=ans[l1][j].ud+1;

                }

                if(s[i][j]==s[i][j-1])

                {

                    ans[l][j].lr=ans[l][j-1].lr+1;

                }

                if(s[i][j]==s[i-1][j-1])

                {

                    ans[l][j].k1=ans[l1][j-1].k1+1;

                }

                if(s[i][j]=='S')

                Snum=Fmax4(Snum,ans[l][j].lr,ans[l][j].ud,ans[l][j].k1);

                else

                snum=Fmax4(snum,ans[l][j].lr,ans[l][j].ud,ans[l][j].k1);



            }

            for(int j=n;j>=1;--j)

            {

                ans[l][j].k2=1;

                if(s[i][j]==s[i-1][j+1])

                {

                    ans[l][j].k2=ans[l1][j+1].k2+1;

                }

                if(s[i][j]=='S')

                Snum=max(Snum,ans[l][j].k2);

                else

                snum=max(snum,ans[l][j].k2);

            }

        }



        //cout<<Snum<<" "<<snum<<endl;

        if(Snum>snum)

        {

            printf("S\n%d\n",Snum);

        }else if(snum>Snum)

        {

            printf("s\n%d\n",snum);

        }else

        {

            printf("?\n%d",snum);

        }

    }

    return 0;

}