답안 #484200

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
484200	2021-11-02T11:27:36 Z	nehasane	Mecho (IOI09_mecho)	C++14	100 / 100	642 ms	7632 KB

mecho

#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 800;
vector <string> field(MAX_N);
bool bees_visited[MAX_N][MAX_N], mecho_visited[MAX_N][MAX_N];
int mecho_dis[MAX_N][MAX_N], bees_dis[MAX_N][MAX_N];
queue <pair <int, int>> mecho_q, bees_q;
int dx[] = {-1, 1, 0, 0};
int dy[] = {0, 0, -1, 1};
int n, s;
bool valid_sq(int x, int y, bool is_mecho){
    if (x >= 0 && x < n && y >= 0 && y < n){
        if (is_mecho && (field[x][y] == 'G' || field[x][y] == 'D' || field[x][y] == 'M'))
            return true;
        else if (!is_mecho && (field[x][y] == 'G' || field[x][y] == 'M'))
            return true;
        return false;
    }
    return false;
}
int main()
{
    // freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
    cin >> n >> s;
    for (int i = 0; i < n; i++)
        cin >> field[i];
    vector <pair <int, int>> hives;
    int mechox, mechoy, home_x, home_y;
    //find starting points position
    for (int i = 0; i < n; i++){
        for (int j = 0; j < n; j++){
            if (field[i][j] == 'M'){
                mechox = i;
                mechoy = j;
            }else if (field[i][j] == 'H'){
                hives.push_back({i, j});
            }else if (field[i][j] == 'D'){
                home_x = i;
                home_y = j;
            }
        }
    }
    int l = 0, r = n*n;
    while (l <= r){
        int eating_time = (l + r) / 2;
        memset(bees_visited, false, sizeof(bees_visited));
        memset(mecho_visited, false, sizeof(mecho_visited));
        memset(bees_dis, 0, sizeof(bees_dis));
        memset(mecho_dis, 0, sizeof(mecho_dis));
        //move bees
        for (auto i : hives){
            bees_q.push({i.first, i.second});
            bees_visited[i.first][i.second] = true;
        }
        while (!bees_q.empty()){
            int x = bees_q.front().first, y = bees_q.front().second;
            bees_q.pop();
            for (int i = 0; i < 4; i++){
                int nx = x + dx[i], ny = y + dy[i];
                if (valid_sq(nx, ny, false) && !bees_visited[nx][ny]){
                    bees_dis[nx][ny] = bees_dis[x][y] + 1;    
                    bees_q.push({nx, ny});
                    bees_visited[nx][ny] = true;
                }
            }
        }
        mecho_q.push({mechox, mechoy});
        mecho_visited[mechox][mechoy] = true;
        if (bees_dis[mechox][mechoy] <= eating_time)
            mecho_q.pop();
        while (!mecho_q.empty()){
            int x = mecho_q.front().first, y = mecho_q.front().second;
            mecho_q.pop();
            for (int i = 0; i < 4; i++){
                int nx = x + dx[i], ny = y + dy[i];
                if (valid_sq(nx, ny, true) && !mecho_visited[nx][ny] && (mecho_dis[x][y] + 1) / s < bees_dis[nx][ny] - eating_time){
                    mecho_visited[nx][ny] = true;
                    mecho_q.push({nx, ny});
                    mecho_dis[nx][ny] = mecho_dis[x][y] + 1;
                }
            }
        }
        bool mecho_reached = false;
        for (int i = 0; i < 4; i++){
            int nx = home_x+ dx[i], ny = home_y + dy[i];
            if (valid_sq(nx, ny, true)){
                if (bees_dis[nx][ny] - eating_time > (mecho_dis[nx][ny] / s) && mecho_visited[nx][ny]){
                    mecho_reached = true;
                    break;
                }
            }
        }
        if (mecho_reached)
            l = eating_time + 1;
        else
            r = eating_time - 1;
        }
    cout << l - 1 << '\n';
}

Compilation message

mecho.cpp: In function 'int main()':
mecho.cpp:70:36: warning: 'mechoy' may be used uninitialized in this function [-Wmaybe-uninitialized]
   70 |         if (bees_dis[mechox][mechoy] <= eating_time)
      |             ~~~~~~~~~~~~~~~~~~~~~~~^
mecho.cpp:70:36: warning: 'mechox' may be used uninitialized in this function [-Wmaybe-uninitialized]
mecho.cpp:86:37: warning: 'home_y' may be used uninitialized in this function [-Wmaybe-uninitialized]
   86 |             int nx = home_x+ dx[i], ny = home_y + dy[i];
      |                                     ^~
mecho.cpp:86:17: warning: 'home_x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   86 |             int nx = home_x+ dx[i], ny = home_y + dy[i];
      |                 ^~

Subtask #1

100.0 / 100.0

#	결과	실행 시간	메모리	Grader output
1	Correct	4 ms	6604 KB	Output is correct
2	Correct	4 ms	6476 KB	Output is correct
3	Correct	3 ms	6476 KB	Output is correct
4	Correct	3 ms	6476 KB	Output is correct
5	Correct	4 ms	6476 KB	Output is correct
6	Correct	4 ms	6476 KB	Output is correct
7	Correct	481 ms	7440 KB	Output is correct
8	Correct	4 ms	6476 KB	Output is correct
9	Correct	4 ms	6476 KB	Output is correct
10	Correct	4 ms	6476 KB	Output is correct
11	Correct	4 ms	6476 KB	Output is correct
12	Correct	11 ms	6476 KB	Output is correct
13	Correct	6 ms	6476 KB	Output is correct
14	Correct	7 ms	6476 KB	Output is correct
15	Correct	5 ms	6476 KB	Output is correct
16	Correct	6 ms	6476 KB	Output is correct
17	Correct	5 ms	6580 KB	Output is correct
18	Correct	5 ms	6476 KB	Output is correct
19	Correct	4 ms	6476 KB	Output is correct
20	Correct	4 ms	6476 KB	Output is correct
21	Correct	5 ms	6476 KB	Output is correct
22	Correct	5 ms	6476 KB	Output is correct
23	Correct	6 ms	6476 KB	Output is correct
24	Correct	7 ms	6580 KB	Output is correct
25	Correct	9 ms	6580 KB	Output is correct
26	Correct	7 ms	6476 KB	Output is correct
27	Correct	9 ms	6588 KB	Output is correct
28	Correct	7 ms	6560 KB	Output is correct
29	Correct	8 ms	6476 KB	Output is correct
30	Correct	8 ms	6476 KB	Output is correct
31	Correct	7 ms	6512 KB	Output is correct
32	Correct	9 ms	6476 KB	Output is correct
33	Correct	38 ms	6732 KB	Output is correct
34	Correct	38 ms	6752 KB	Output is correct
35	Correct	71 ms	6732 KB	Output is correct
36	Correct	47 ms	6732 KB	Output is correct
37	Correct	48 ms	6732 KB	Output is correct
38	Correct	94 ms	6732 KB	Output is correct
39	Correct	63 ms	6780 KB	Output is correct
40	Correct	89 ms	6732 KB	Output is correct
41	Correct	122 ms	6784 KB	Output is correct
42	Correct	73 ms	6988 KB	Output is correct
43	Correct	74 ms	7052 KB	Output is correct
44	Correct	170 ms	7044 KB	Output is correct
45	Correct	90 ms	6988 KB	Output is correct
46	Correct	84 ms	6988 KB	Output is correct
47	Correct	179 ms	7100 KB	Output is correct
48	Correct	124 ms	7116 KB	Output is correct
49	Correct	123 ms	7140 KB	Output is correct
50	Correct	208 ms	7132 KB	Output is correct
51	Correct	123 ms	7116 KB	Output is correct
52	Correct	132 ms	7176 KB	Output is correct
53	Correct	275 ms	7208 KB	Output is correct
54	Correct	147 ms	7244 KB	Output is correct
55	Correct	155 ms	7244 KB	Output is correct
56	Correct	299 ms	7244 KB	Output is correct
57	Correct	164 ms	7276 KB	Output is correct
58	Correct	176 ms	7276 KB	Output is correct
59	Correct	355 ms	7304 KB	Output is correct
60	Correct	199 ms	7312 KB	Output is correct
61	Correct	194 ms	7320 KB	Output is correct
62	Correct	428 ms	7344 KB	Output is correct
63	Correct	532 ms	7336 KB	Output is correct
64	Correct	642 ms	7244 KB	Output is correct
65	Correct	559 ms	7336 KB	Output is correct
66	Correct	516 ms	7232 KB	Output is correct
67	Correct	561 ms	7364 KB	Output is correct
68	Correct	447 ms	7372 KB	Output is correct
69	Correct	498 ms	7372 KB	Output is correct
70	Correct	470 ms	7360 KB	Output is correct
71	Correct	519 ms	7364 KB	Output is correct
72	Correct	452 ms	7356 KB	Output is correct
73	Correct	437 ms	7624 KB	Output is correct
74	Correct	461 ms	7632 KB	Output is correct
75	Correct	489 ms	7628 KB	Output is correct
76	Correct	456 ms	7628 KB	Output is correct
77	Correct	484 ms	7628 KB	Output is correct
78	Correct	477 ms	7600 KB	Output is correct
79	Correct	469 ms	7620 KB	Output is correct
80	Correct	442 ms	7596 KB	Output is correct
81	Correct	486 ms	7500 KB	Output is correct
82	Correct	469 ms	7620 KB	Output is correct
83	Correct	486 ms	7500 KB	Output is correct
84	Correct	474 ms	7588 KB	Output is correct
85	Correct	543 ms	7500 KB	Output is correct
86	Correct	508 ms	7604 KB	Output is correct
87	Correct	486 ms	7560 KB	Output is correct
88	Correct	477 ms	7508 KB	Output is correct
89	Correct	497 ms	7516 KB	Output is correct
90	Correct	478 ms	7496 KB	Output is correct
91	Correct	487 ms	7452 KB	Output is correct
92	Correct	520 ms	7500 KB	Output is correct