Submission #724833

#	Time	Username	Problem	Language	Result	Execution time	Memory
724833		chanhchuong123	Mecho (IOI09_mecho)	C++14	89 / 100	191 ms	6224 KiB

mecho

#include <bits/stdc++.h>
using namespace std;
#define task ""
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define FORD(i, a, b) for (int i = (b), _a = (a); i >= _a; --i)

template <typename T1, typename T2> bool minimize(T1 &a, T2 b) {
	if (a > b) {a = b; return true;} return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b) {
	if (a < b) {a = b; return true;} return false;
}

const int dx[] = {-1, 0, 0, +1};
const int dy[] = {0, -1, +1, 0};

const int MAX = 800;
int n, S;
int xM, yM;
int xD, yD;
char a[MAX][MAX];
int bee[MAX][MAX];
int bear[MAX][MAX];
queue<pair<int, int>> q;

bool ok(int add) {
    memset(bear, -1, sizeof bear);
    q.push({xM, yM});
    bear[xM][yM] = 0;
    while (q.size()) {
        int u = q.front().fi;
        int v = q.front().se;
        q.pop();

        for (int i = 0; i < 4; ++i) {
            int x = u + dx[i], y = v + dy[i];
            if (x < 0 || x >= n) continue;
            if (y < 0 || y >= n) continue;
            if (a[x][y] == 'M' || a[x][y] == 'G' || a[x][y] == 'D') {
                int candidate = bear[u][v] + 1;
                if (add + candidate / S < bee[x][y]) {
                    if (bear[x][y] == -1) {
                        q.push({x, y});
                        bear[x][y] = candidate;
                    }
                }
            }
        }
    }
    for (int i = 0; i < 4; ++i) {
        int x = xD + dx[i], y = yD + dy[i];
        if (x < 0 || x >= n) continue;
        if (y < 0 || y >= n) continue;
        if (bear[x][y] == -1) continue;
        if (a[x][y] == 'T' || a[x][y] == 'H') continue;
        if (add + bear[x][y] / S < bee[x][y]) return true;
    }
    return false;
}

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);
	}

    cin >> n >> S;
    memset(bee, -1, sizeof bee);
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            cin >> a[i][j];
            if (a[i][j] == 'H') {
                bee[i][j] = 0;
                q.push({i, j});
            }
            if (a[i][j] == 'D') {
                xD = i, yD = j;
            }
            if (a[i][j] == 'M') {
                xM = i, yM = j;
            }
        }
    }
    //
    while (q.size()) {
        int u = q.front().fi;
        int v = q.front().se;
        q.pop();

        for (int i = 0; i < 4; ++i) {
            int x = u + dx[i], y = v + dy[i];
            if (x < 0 || x >= n) continue;
            if (y < 0 || y >= n) continue;
            if (a[x][y] != 'T' && a[x][y] != 'D') {
                if (bee[x][y] == -1) {
                    q.push({x, y});
                    bee[x][y] = bee[u][v] + 1;
                }
            }
        }
    }
    //
    int l = -1, r = 1e9;
    while (r - l > 1) {
        int mid = l + r >> 1;
        if (ok(mid)) l = mid;
        else r = mid;
    }
    cout << l;
	return 0;
}

Compilation message (stderr)

mecho.cpp: In function 'int main()':
mecho.cpp:112:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  112 |         int mid = l + r >> 1;
      |                   ~~^~~
mecho.cpp:70:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |   freopen(task".inp", "r", stdin);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
mecho.cpp:71:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |   freopen(task".out", "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 89 / 100