Submission #1078903

#	Time	Username	Problem	Language	Result	Execution time	Memory
1078903		Yang8on	Mecho (IOI09_mecho)	C++17	5 / 100	213 ms	65536 KiB

mecho

#include <bits/stdc++.h>
#define Y8o "main"
#define maxn (int) 805
#define ll long long
#define pii pair<int, int>
#define gb(i, j) ((i >> j) & 1)
#define all(x) x.begin(), x.end()
#define _left id * 2, l, mid
#define _right id * 2 + 1, mid + 1, r

#define f first
#define s second

using namespace std;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll GetRandom(ll l, ll r) {
    return uniform_int_distribution<ll> (l, r) (rng);
}
void iof() {
    if(fopen(Y8o".inp", "r"))
    {
        freopen(Y8o".inp", "r", stdin);
//        freopen(Y8o".out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(NULL), cout.tie(NULL);
}
void ctime() {
    cerr << "\n" << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
}

int n, S;
pii st, en;
char a[maxn][maxn];
int lim[maxn][maxn], dp[maxn][maxn];
int dx[] = { 1, -1, 0, 0 };
int dy[] = { 0, 0, -1, 1 };
bool exist(int u, int v) { return 1 <= u && u <= n && 1 <= v && v <= n && a[u][v] != 'T'; }

bool check(int tg) {
    for(int i = 1; i <= n; i ++) for(int j = 1; j <= n; j ++)
        dp[i][j] = 1e9;
    dp[st.f][st.s] = tg * S;

    queue<pii> q;
    q.push(st);
    while(q.size()) {
        int i, j; tie(i, j) = q.front();
        q.pop();
        for(int t = 0; t <= 3; t ++) {
            int u = i + dx[t], v = j + dy[t];
            if(exist(u, v) && dp[i][j] + 1 < lim[u][v]) {
                dp[u][v] = dp[i][j] + 1;
                q.push({ u, v });
            }
        }
    }
    return dp[en.f][en.s] < lim[en.f][en.s];
}

void solve() {
    cin >> n >> S;
    for(int i = 1; i <= n; i ++) for(int j = 1; j <= n; j ++) {
        cin >> a[i][j];
        if(a[i][j] == 'M') st = {i, j};
        else if(a[i][j] == 'D') en = {i, j};
    }

    queue<pii> q;
    for(int i = 1; i <= n; i ++) for(int j = 1; j <= n; j ++) {
        lim[i][j] = 1e9;
        if(a[i][j] == 'H') lim[i][j] = 0, q.push({ i, j });
    }
    while(q.size()) {
        int i, j; tie(i, j) = q.front();
        q.pop();
        for(int t = 0; t <= 3; t ++) {
            int u = i + dx[t], v = j + dy[t];
            if(exist(u, v)) {
                if(lim[u][v] > lim[i][j] + S) {
                    lim[u][v] = lim[i][j] + S;
                    q.push({ u, v });
                }
            }
        }
    }

    int l = 1, r = n * n;
    while(l <= r) {
        int mid = (l + r) >> 1;
        if(check(mid)) l = mid + 1;
        else r = mid - 1;
    }
    cout << r;
}

int main() {
    iof();

    int nTest = 1;
//    cin >> nTest;

    while(nTest --) {
        solve();
    }

    ctime();
    return 0;
}

Compilation message (stderr)

mecho.cpp: In function 'void iof()':
mecho.cpp:23:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   23 |         freopen(Y8o".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 100