Rover

// prof. Mircea Lupse-Turpan - Liceul Teoretic Grigore Moisil Timisoara - 100 puncte
#include <fstream>
#include <deque>
#include <cstring>
using namespace std;

ifstream fin("rover.in");
ofstream fout("rover.out");

const int NMax = 505;
const int oo = 10000;
int A[NMax][NMax],DP[NMax][NMax];
int V,N,G;
int dx[] = {-1,0,1,0}, dy[] = {0,1,0,-1};
deque <pair <int,int> > Q;

void Read()
{
    fin >> V >> N;
    if(V == 1) fin >> G;
    for(int i = 1; i <= N; ++i)
        for(int j = 1; j <= N; ++j)
            fin >> A[i][j];
}

inline bool Inside(int x, int y)
{
    return ( (x >= 1) && (x <= N) && (y >= 1) && (y <= N) );
}

void Solve1()
{
    memset(DP,-1,sizeof(DP));
    Q.push_back(make_pair(1,1));
    DP[1][1] = 0;

    while(!Q.empty())
    {
        int X = Q.front().first, Y = Q.front().second;
        Q.pop_front();
        for(int k = 0; k < 4; k++)
        {
            int NewX = X + dx[k], NewY = Y + dy[k];
            if(Inside(NewX,NewY) && DP[NewX][NewY] == -1)
            {
                if(A[NewX][NewY] < G)
                {
                    DP[NewX][NewY] = DP[X][Y] + 1;
                    Q.push_back(make_pair(NewX,NewY));
                }
                else
                {
                    DP[NewX][NewY] = DP[X][Y];
                    Q.push_front(make_pair(NewX,NewY));
                }
            }
        }
    }
    fout << DP[N][N] << "\n";
}

bool Lee(int Value)
{
    memset(DP,-1,sizeof(DP));
    Q.push_back(make_pair(1,1));
    DP[1][1] = 0;
    while(!Q.empty())
    {
        int X = Q.front().first, Y = Q.front().second;
        Q.pop_front();
        for(int k = 0; k < 4; k++)
        {
            int NewX = X + dx[k], NewY = Y + dy[k];
            if(Inside(NewX,NewY) && DP[NewX][NewY] == -1)
            {
                if(A[NewX][NewY] >= Value)
                {
                    DP[NewX][NewY] = DP[X][Y] + 1;
                    Q.push_back(make_pair(NewX,NewY));
                }
            }
        }
    }
    return (DP[N][N] != -1);
}

void Solve2()
{
    int Left = 1, Right = oo, Sol = -1;

    while(Left <= Right)
    {
        int Mid = (Left + Right) / 2;
        if(Lee(Mid))
        {
            Sol = Mid;
            Left = Mid + 1;
        }
        else
            Right = Mid - 1;
    }
    fout << Sol << "\n";
}


int main()
{
    Read();
    if(V == 1)
        Solve1();
    else
        Solve2();
    return 0;
}