POJ2111 Millenium Leapcow

#include<iostream>
#include<vector>
#include<cstdio>
using namespace std;
#define pb push_back
#define mp make_pair
#define se second
#define fs first
#define LL long long
#define CLR(x) memset(x,0,sizeof x)
#define MC(x,y) memcpy(x,y,sizeof(x))  
#define SZ(x) ((int)(x).size())
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1 
typedef pair<int,int> P;
const double eps=1e-9;
const int maxn=200100;
const int mod=1e9+7;
const int INF=1e9;

int M[370][370],dp[370][370];
P path[370][370];
vector<P> v;
int n;

int dx[8]={1,1,2,2,-1,-1,-2,-2};
int dy[8]={-2,2,-1,1,2,-2,1,-1};

int DP(int x,int y)
{
    int &m=dp[x][y];
    if(m)  return m;
    m=1;
    for(int i=0;i<8;i++)
    {
        int nx=x+dx[i];
        int ny=y+dy[i];
        if(nx>=1&&nx<=n&&ny>=1&&ny<=n&&M[nx][ny]>M[x][y])
        {
            if(DP(nx,ny)+1>m)
            {
                m=DP(nx,ny)+1;
                path[x][y]=mp(nx,ny);
            }
            else if(DP(nx,ny)+1==m&&M[path[x][y].fs][path[x][y].se]>M[nx][ny]) path[x][y]=mp(nx,ny);
        }
    }
    return m;
}

int main()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++)
    for(int j=1;j<=n;j++) scanf("%d",&M[i][j]);
    int Max=1;
    for(int i=1;i<=n;i++)
    for(int j=1;j<=n;j++)
    {
        if(Max<DP(i,j))
        {
            Max=DP(i,j);
            v.clear();
            v.pb(mp(i,j));
        }
        else if(Max==DP(i,j)) v.pb(mp(i,j));
    }
    int key,keyx,keyy;
    key=INF;
    for(int i=0;i<v.size();i++)
    {
        if(key>M[v[i].fs][v[i].se])
        {
            key=M[v[i].fs][v[i].se];
            keyx=v[i].fs;
            keyy=v[i].se;
        }
    }
    printf("%d\n",Max);
    while(true)
    {
        printf("%d\n",key);
        int fis=path[keyx][keyy].fs,sec=path[keyx][keyy].se;
        keyx=fis;keyy=sec;
        key=M[keyx][keyy];
        if(!keyx) break;
    }
    return 0;
}