답안 #491407

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
491407	2021-12-02T01:11:03 Z	nehasane	Mecho (IOI09_mecho)	C++14	0 / 100	1000 ms	6768 KB

mecho

#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 800;
vector <string> field(MAX_N);
int n, s;
bool valid_sq(int x, int y){
    if (x >= 0 && x < n && y >= 0 && y < n && (field[x][y] == 'G' || field[x][y] == 'M'))
        return true;
    return false;
}
int main()
{
    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 x and y coordinates for for Mecho, the bees and the cave
    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 dx[] = {-1, 0, 1, 0};
    int dy[] = {0, -1, 0, 1};

    //  binary search on waiting time
    int l = 0, r = n * n;
    queue <pair <int, int>> q;
    while (l <= r){
        vector <vector <bool>> bees_visited(n, vector<bool>(n, false));
        vector <vector <bool>> mecho_visited(n, vector<bool>(n, false));
        vector <vector <int>> bees_time(n, vector<int>(n, 0));
        vector <vector <int>> mecho_time(n, vector<int>(n, 0));
        
        int eating_time = (l + r) / 2;

        //  move bees
        for (auto i : hives){
            q.push({i.first, i.second});
            bees_visited[i.first][i.second] = true;
        }
        
        while (!q.empty()){
            int x = q.front().first, y = q.front().second;
            q.pop();
            for (int i = 0; i < 4; i++){
                int nx = x + dx[i], ny = y + dy[i];
                if (valid_sq(nx, ny) && !bees_visited[nx][ny]){
                    bees_time[nx][ny] = bees_time[x][y] + 1;    
                    q.push({nx, ny});
                    bees_visited[nx][ny] = true;
                }
            }
        }
        
        
        //  move Mecho
        q.push({mechox, mechoy});
        mecho_visited[mechox][mechoy] = true;
        if (bees_time[mechox][mechoy] <= eating_time)
            q.pop();
        while (!q.empty()){
            int x = q.front().first, y = q.front().second;
            q.pop();
            for (int i = 0; i < 4; i++){
                int nx = x + dx[i], ny = y + dy[i];
                /*  check if mecho reaces node[x][y] before the bees
                    divide the time mecho takes to reach a node by s, since mecho
                    walks s steps at a time.
                    substract the eating time from the time taken for the bees to 
                    reach the node, because that time was used by mecho for eating
                */
                if (valid_sq(nx, ny) && !mecho_visited[nx][ny] && 
                    (mecho_time[x][y] + 1) / s < bees_time[nx][ny] - eating_time){
                        mecho_visited[nx][ny] = true;
                        q.push({nx, ny});
                        mecho_time[nx][ny] = mecho_time[x][y] + 1;
                    }
                }
        
            //  check if mecho reached a node surrounding his cave before the bees
            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) && (mecho_time[nx][ny] / s) < bees_time[nx][ny] - eating_time
                    && mecho_visited[nx][ny]){
                        mecho_reached = true;
                    }
            }
            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:69:29: warning: 'mechox' may be used uninitialized in this function [-Wmaybe-uninitialized]
   69 |         mecho_visited[mechox][mechoy] = true;
      |                             ^
mecho.cpp:94:41: warning: 'home_y' may be used uninitialized in this function [-Wmaybe-uninitialized]
   94 |                 int nx = home_x+ dx[i], ny = home_y + dy[i];
      |                                         ^~
mecho.cpp:94:21: warning: 'home_x' may be used uninitialized in this function [-Wmaybe-uninitialized]
   94 |                 int nx = home_x+ dx[i], ny = home_y + dy[i];
      |                     ^~

Subtask #1

0.0 / 100.0

#	결과	실행 시간	메모리	Grader output
1	Execution timed out	1089 ms	3024 KB	Time limit exceeded
2	Execution timed out	1089 ms	2304 KB	Time limit exceeded
3	Execution timed out	1083 ms	2628 KB	Time limit exceeded
4	Execution timed out	1070 ms	1792 KB	Time limit exceeded
5	Execution timed out	1085 ms	1976 KB	Time limit exceeded
6	Execution timed out	1095 ms	912 KB	Time limit exceeded
7	Execution timed out	1070 ms	6488 KB	Time limit exceeded
8	Execution timed out	1080 ms	708 KB	Time limit exceeded
9	Execution timed out	1084 ms	668 KB	Time limit exceeded
10	Execution timed out	1088 ms	716 KB	Time limit exceeded
11	Execution timed out	1098 ms	608 KB	Time limit exceeded
12	Execution timed out	1090 ms	360 KB	Time limit exceeded
13	Execution timed out	1094 ms	368 KB	Time limit exceeded
14	Execution timed out	1084 ms	460 KB	Time limit exceeded
15	Execution timed out	1073 ms	580 KB	Time limit exceeded
16	Execution timed out	1096 ms	704 KB	Time limit exceeded
17	Execution timed out	1090 ms	524 KB	Time limit exceeded
18	Execution timed out	1096 ms	568 KB	Time limit exceeded
19	Execution timed out	1076 ms	588 KB	Time limit exceeded
20	Execution timed out	1097 ms	608 KB	Time limit exceeded
21	Execution timed out	1094 ms	460 KB	Time limit exceeded
22	Execution timed out	1051 ms	580 KB	Time limit exceeded
23	Execution timed out	1087 ms	500 KB	Time limit exceeded
24	Execution timed out	1085 ms	512 KB	Time limit exceeded
25	Execution timed out	1091 ms	488 KB	Time limit exceeded
26	Execution timed out	1091 ms	452 KB	Time limit exceeded
27	Execution timed out	1090 ms	396 KB	Time limit exceeded
28	Execution timed out	1082 ms	504 KB	Time limit exceeded
29	Execution timed out	1081 ms	632 KB	Time limit exceeded
30	Execution timed out	1087 ms	756 KB	Time limit exceeded
31	Execution timed out	1057 ms	708 KB	Time limit exceeded
32	Execution timed out	1091 ms	396 KB	Time limit exceeded
33	Execution timed out	1084 ms	1484 KB	Time limit exceeded
34	Execution timed out	1093 ms	1484 KB	Time limit exceeded
35	Execution timed out	1086 ms	1532 KB	Time limit exceeded
36	Execution timed out	1091 ms	1872 KB	Time limit exceeded
37	Execution timed out	1099 ms	1868 KB	Time limit exceeded
38	Execution timed out	1095 ms	1868 KB	Time limit exceeded
39	Execution timed out	1082 ms	2252 KB	Time limit exceeded
40	Execution timed out	1085 ms	2172 KB	Time limit exceeded
41	Execution timed out	1091 ms	2260 KB	Time limit exceeded
42	Execution timed out	1093 ms	2824 KB	Time limit exceeded
43	Execution timed out	1081 ms	2892 KB	Time limit exceeded
44	Execution timed out	1093 ms	2892 KB	Time limit exceeded
45	Execution timed out	1091 ms	3360 KB	Time limit exceeded
46	Execution timed out	1094 ms	3276 KB	Time limit exceeded
47	Execution timed out	1079 ms	3364 KB	Time limit exceeded
48	Execution timed out	1096 ms	3920 KB	Time limit exceeded
49	Execution timed out	1089 ms	3916 KB	Time limit exceeded
50	Execution timed out	1084 ms	3928 KB	Time limit exceeded
51	Execution timed out	1080 ms	4428 KB	Time limit exceeded
52	Execution timed out	1086 ms	4428 KB	Time limit exceeded
53	Execution timed out	1095 ms	4444 KB	Time limit exceeded
54	Execution timed out	1095 ms	5068 KB	Time limit exceeded
55	Execution timed out	1071 ms	5060 KB	Time limit exceeded
56	Execution timed out	1093 ms	4952 KB	Time limit exceeded
57	Execution timed out	1089 ms	5708 KB	Time limit exceeded
58	Execution timed out	1092 ms	5704 KB	Time limit exceeded
59	Execution timed out	1085 ms	5712 KB	Time limit exceeded
60	Execution timed out	1091 ms	6348 KB	Time limit exceeded
61	Execution timed out	1093 ms	6272 KB	Time limit exceeded
62	Execution timed out	1087 ms	6380 KB	Time limit exceeded
63	Execution timed out	1098 ms	6384 KB	Time limit exceeded
64	Execution timed out	1091 ms	6508 KB	Time limit exceeded
65	Execution timed out	1094 ms	6392 KB	Time limit exceeded
66	Execution timed out	1089 ms	6384 KB	Time limit exceeded
67	Execution timed out	1080 ms	6312 KB	Time limit exceeded
68	Execution timed out	1094 ms	6452 KB	Time limit exceeded
69	Execution timed out	1099 ms	6404 KB	Time limit exceeded
70	Execution timed out	1089 ms	6324 KB	Time limit exceeded
71	Execution timed out	1098 ms	6328 KB	Time limit exceeded
72	Execution timed out	1092 ms	6416 KB	Time limit exceeded
73	Execution timed out	1098 ms	6724 KB	Time limit exceeded
74	Execution timed out	1091 ms	6688 KB	Time limit exceeded
75	Execution timed out	1096 ms	6680 KB	Time limit exceeded
76	Execution timed out	1097 ms	6724 KB	Time limit exceeded
77	Execution timed out	1094 ms	6568 KB	Time limit exceeded
78	Execution timed out	1099 ms	6764 KB	Time limit exceeded
79	Execution timed out	1092 ms	6608 KB	Time limit exceeded
80	Execution timed out	1093 ms	6768 KB	Time limit exceeded
81	Execution timed out	1096 ms	6724 KB	Time limit exceeded
82	Execution timed out	1093 ms	6644 KB	Time limit exceeded
83	Execution timed out	1089 ms	6600 KB	Time limit exceeded
84	Execution timed out	1095 ms	6608 KB	Time limit exceeded
85	Execution timed out	1097 ms	6608 KB	Time limit exceeded
86	Execution timed out	1089 ms	6608 KB	Time limit exceeded
87	Execution timed out	1086 ms	6608 KB	Time limit exceeded
88	Execution timed out	1069 ms	6544 KB	Time limit exceeded
89	Execution timed out	1088 ms	6556 KB	Time limit exceeded
90	Execution timed out	1092 ms	6632 KB	Time limit exceeded
91	Execution timed out	1092 ms	6644 KB	Time limit exceeded
92	Execution timed out	1091 ms	6548 KB	Time limit exceeded