Submission #861305

#	Time	Username	Problem	Language	Result	Execution time	Memory
861305		nnhzzz	Tracks in the Snow (BOI13_tracks)	C++14	97.81 / 100	578 ms	137648 KiB

tracks

#include<bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i = (a); i<=(b); ++i)
#define REPD(i,a,b) for(int i = (a); i>=(b); --i)
#define REPDIS(i,a,b,c) for(int i = (a); i<=(b); i += c)
#define task "test"
#define task1 "nnhzzz"
#define ALL(x) (x).begin(),(x).end()
#define SZ(x) (int)(x).size()
#define MASK(x) (1LL<<x)
#define BIT(x,i) ((x>>i)&1LL)
#define vi vector<int>
#define vvi vector<vi>
#define pii pair<int,int>
#define vpii vector<pii>
#define fi first
#define se second
#define ld long double
#define ll long long

//-------------------------------------------------------------------------------//
template<typename T> bool mini(T &a, T b){if(a>b){a=b;return true;}return false;}
template<typename T> bool maxi(T &a, T b){if(a<b){a=b;return true;}return false;}
//-------------------------------------------------------------------------------//
const int MAXN = 4e3+7,N = 1e5+7,inf = 1e9,LOG = 20;
const int MOD = 1e9+7,MOD1 = 123456789;
const int dx[] = {1,0,0,-1};
const int dy[] = {0,1,-1,0};
//-------------------------------------------------------------------------------//

char c[MAXN][MAXN];
int d[MAXN][MAXN];
int n,m,res = 0;

bool ok(int x, int y){
    return (x>=1 && y>=1 && x<=n && y<=m);
}

void solve(){
    cin >> n >> m;
    REP(i,1,n) REP(j,1,m) cin >> c[i][j];
    deque<pii> q; d[1][1] = 1;
    q.emplace_back(1,1);
    while(SZ(q)!=0){
        int x = q.front().fi,y = q.front().se; q.pop_front();
        REP(i,0,3){
            int nx = x+dx[i],ny = y+dy[i];
            if(ok(nx,ny)==false || c[nx][ny]=='.' || d[nx][ny]!=0) continue;
            if(c[x][y]==c[nx][ny]){
                d[nx][ny] = d[x][y];
                q.emplace_front(nx,ny);
            }else{
                maxi(res,d[x][y]+1);
                d[nx][ny] = d[x][y]+1;
                q.emplace_back(nx,ny);
            }
        }
    }
    cout << res;
}

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if(fopen(task".inp","r")){
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    if(fopen(task1".inp","r")){
        freopen(task1".inp","r",stdin);
        freopen(task1".out","w",stdout);
    }
    solve();
    return 0;
}

Compilation message (stderr)

tracks.cpp: In function 'int main()':
tracks.cpp:68:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:69:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:72:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |         freopen(task1".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
tracks.cpp:73:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen(task1".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 67.8125 / 70