Submission #593765

#	Time	Username	Problem	Language	Result	Execution time	Memory
593765		messiuuuuu	Pohlepko (COCI16_pohlepko)	C++14	80 / 80	27 ms	19912 KiB

pohlepko

#include<bits/stdc++.h>
#define task "C"
#define ll long long
#define ld long double
#define fi first
#define se second
#define pb push_back
using namespace std;
const int MAXN = 2e3 + 5;
const ll INF = 1e18 + 5;

int m, n;
char c[MAXN][MAXN];

void Input()
{
    cin >> m >> n;
    for (int i = 1; i <= m; i++)
    {
        string s;
        cin >> s;
        for (int j = 0; j < n; j++)
            c[i][j + 1] = s[j];
    }
}

bool trace[MAXN][MAXN], ava[MAXN][MAXN], ava2[MAXN][MAXN];

pair<int, int> down(pair<int, int> u)
{
    return {u.fi + 1, u.se};
}

pair<int, int> rght(pair<int, int> u)
{
    return {u.fi, u.se + 1};
}

bool chk(pair<int, int> u)
{
    return (u.fi >= 1 && u.se >= 1 && u.fi <= m && u.se <= n);
}

void Solve()
{
    deque<pair<int, int>> Q;
    Q.pb({1, 1});
    ava[1][1] = 1;
    while (true)
    {
        if (ava[m][n])
            break;
        vector<pair<int, int>> vc;
        while (!Q.empty())
        {
            auto u = Q.front();
            //cerr << u.fi << ' ' << u.se << '\n';
            auto v = down(u);
            if (chk(v) && !ava2[v.fi][v.se])
            {
                ava2[v.fi][v.se] = 1;
                trace[v.fi][v.se] = 0;
                vc.pb(v);
            }
            v = rght(u);
            if (chk(v) && !ava2[v.fi][v.se])
            {
                ava2[v.fi][v.se] = 1;
                trace[v.fi][v.se] = 1;
                vc.pb(v);
            }
            Q.pop_front();
        }
        char minc = 'z';
        for (auto p : vc)
            minc = min(minc, c[p.fi][p.se]);
        for (auto p : vc)
        {
            //cerr << p.fi << ' ' << p.se << '\n';
            ava2[p.fi][p.se] = 0;
            if (c[p.fi][p.se] == minc && !ava[p.fi][p.se])
            {
                Q.pb(p);
                ava[p.fi][p.se] = 1;
            }
        }
    }
    vector<char> res;
    pair<int, int> en = {m, n};
    while (en != make_pair(1, 1))
    {
        res.pb(c[en.fi][en.se]);
        if (trace[en.fi][en.se])
            en.se--;
        else
            en.fi--;
    }
    res.pb(c[1][1]);
    reverse(res.begin(), res.end());
    for (char t : res)
        cout << t;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if (fopen(task".INP","r"))
    {
        freopen(task".INP","r",stdin);
        //freopen(task".OUT","w",stdout);
    }
    Input();
    Solve();
}

Compilation message (stderr)

pohlepko.cpp: In function 'int main()':
pohlepko.cpp:110:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  110 |         freopen(task".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 80 / 80