답안 #484160

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
484160	2021-11-02T08:38:53 Z	nehasane	Mecho (IOI09_mecho)	C++14	100 / 100	669 ms	10180 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], eating_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 startx, starty, home_x, home_y;
    //find Mecho's position
    for (int i = 0; i < n; i++){
        for (int j = 0; j < n; j++){
            if (field[i][j] == 'M'){
                startx = i;
                starty = 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]){
                    if (eating_dis[x][y] < eating_time){
                        eating_dis[nx][ny] = eating_dis[x][y] + 1;
                    }else{
                        bees_dis[nx][ny] = bees_dis[x][y] + 1;
                        eating_dis[nx][ny] = INT_MAX;
                    }
                    bees_q.push({nx, ny});
                    bees_visited[nx][ny] = true;
                }
            }
        }
        mecho_q.push({startx, starty});
        mecho_visited[startx][starty] = true;
        if (eating_dis[startx][starty] != INT_MAX)
            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]){
                    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] > (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:75:38: warning: 'starty' may be used uninitialized in this function [-Wmaybe-uninitialized]
   75 |         if (eating_dis[startx][starty] != INT_MAX)
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~^
mecho.cpp:75:38: warning: 'startx' may be used uninitialized in this function [-Wmaybe-uninitialized]
mecho.cpp:91:37: warning: 'home_y' may be used uninitialized in this function [-Wmaybe-uninitialized]
   91 |             int nx = home_x+ dx[i], ny = home_y + dy[i];
      |                                     ^~
mecho.cpp:91:17: warning: 'home_x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   91 |             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	3 ms	6476 KB	Output is correct
2	Correct	4 ms	6476 KB	Output is correct
3	Correct	3 ms	6476 KB	Output is correct
4	Correct	6 ms	6604 KB	Output is correct
5	Correct	6 ms	6604 KB	Output is correct
6	Correct	6 ms	6612 KB	Output is correct
7	Correct	518 ms	9948 KB	Output is correct
8	Correct	6 ms	6604 KB	Output is correct
9	Correct	5 ms	6732 KB	Output is correct
10	Correct	7 ms	6604 KB	Output is correct
11	Correct	4 ms	6604 KB	Output is correct
12	Correct	7 ms	6740 KB	Output is correct
13	Correct	6 ms	6732 KB	Output is correct
14	Correct	6 ms	6732 KB	Output is correct
15	Correct	5 ms	6604 KB	Output is correct
16	Correct	5 ms	6604 KB	Output is correct
17	Correct	5 ms	6604 KB	Output is correct
18	Correct	5 ms	6604 KB	Output is correct
19	Correct	5 ms	6604 KB	Output is correct
20	Correct	4 ms	6604 KB	Output is correct
21	Correct	5 ms	6604 KB	Output is correct
22	Correct	5 ms	6604 KB	Output is correct
23	Correct	5 ms	6732 KB	Output is correct
24	Correct	5 ms	6732 KB	Output is correct
25	Correct	6 ms	6732 KB	Output is correct
26	Correct	6 ms	6732 KB	Output is correct
27	Correct	6 ms	6732 KB	Output is correct
28	Correct	7 ms	6732 KB	Output is correct
29	Correct	7 ms	6700 KB	Output is correct
30	Correct	7 ms	6812 KB	Output is correct
31	Correct	9 ms	6732 KB	Output is correct
32	Correct	8 ms	6732 KB	Output is correct
33	Correct	51 ms	7804 KB	Output is correct
34	Correct	40 ms	7856 KB	Output is correct
35	Correct	100 ms	7832 KB	Output is correct
36	Correct	53 ms	8012 KB	Output is correct
37	Correct	52 ms	7956 KB	Output is correct
38	Correct	104 ms	8016 KB	Output is correct
39	Correct	67 ms	8140 KB	Output is correct
40	Correct	86 ms	8100 KB	Output is correct
41	Correct	135 ms	8192 KB	Output is correct
42	Correct	80 ms	8620 KB	Output is correct
43	Correct	102 ms	8524 KB	Output is correct
44	Correct	186 ms	8624 KB	Output is correct
45	Correct	97 ms	8828 KB	Output is correct
46	Correct	90 ms	8812 KB	Output is correct
47	Correct	239 ms	8828 KB	Output is correct
48	Correct	115 ms	9036 KB	Output is correct
49	Correct	117 ms	9024 KB	Output is correct
50	Correct	247 ms	9084 KB	Output is correct
51	Correct	128 ms	9164 KB	Output is correct
52	Correct	137 ms	9264 KB	Output is correct
53	Correct	367 ms	9164 KB	Output is correct
54	Correct	150 ms	9420 KB	Output is correct
55	Correct	153 ms	9460 KB	Output is correct
56	Correct	367 ms	9356 KB	Output is correct
57	Correct	167 ms	9548 KB	Output is correct
58	Correct	171 ms	9668 KB	Output is correct
59	Correct	393 ms	9548 KB	Output is correct
60	Correct	198 ms	9840 KB	Output is correct
61	Correct	254 ms	9796 KB	Output is correct
62	Correct	434 ms	9844 KB	Output is correct
63	Correct	535 ms	9844 KB	Output is correct
64	Correct	659 ms	9924 KB	Output is correct
65	Correct	565 ms	9804 KB	Output is correct
66	Correct	542 ms	9924 KB	Output is correct
67	Correct	553 ms	9800 KB	Output is correct
68	Correct	531 ms	9872 KB	Output is correct
69	Correct	545 ms	9872 KB	Output is correct
70	Correct	484 ms	9804 KB	Output is correct
71	Correct	522 ms	9932 KB	Output is correct
72	Correct	483 ms	9872 KB	Output is correct
73	Correct	445 ms	10136 KB	Output is correct
74	Correct	585 ms	10140 KB	Output is correct
75	Correct	525 ms	10180 KB	Output is correct
76	Correct	497 ms	10056 KB	Output is correct
77	Correct	580 ms	10136 KB	Output is correct
78	Correct	500 ms	10032 KB	Output is correct
79	Correct	483 ms	10136 KB	Output is correct
80	Correct	540 ms	10104 KB	Output is correct
81	Correct	495 ms	10100 KB	Output is correct
82	Correct	584 ms	10052 KB	Output is correct
83	Correct	579 ms	10172 KB	Output is correct
84	Correct	493 ms	10068 KB	Output is correct
85	Correct	669 ms	10064 KB	Output is correct
86	Correct	599 ms	10064 KB	Output is correct
87	Correct	512 ms	10060 KB	Output is correct
88	Correct	617 ms	10064 KB	Output is correct
89	Correct	525 ms	10052 KB	Output is correct
90	Correct	503 ms	10008 KB	Output is correct
91	Correct	577 ms	10108 KB	Output is correct
92	Correct	543 ms	10096 KB	Output is correct