oj.uz

Submission #475813

# Submission time Handle Problem Language Result Execution time Memory
475813 2021-09-24T06:02:36 Z clams Tracks in the Snow (BOI13_tracks) C++17
100 / 100
 760 ms 112816 KB 
/*
 * Author: bubu2006
**/

#include <bits/stdc++.h>
using namespace std;

int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    
    int H, W;
    cin >> H >> W;
    
    vector<string> m(H);
    for(int i = 0; i < H; i++) cin >> m[i];
    
    vector<int> dy = {0, 0, -1, 1};
    vector<int> dx = {1, -1, 0, 0};
    
    const int INF = 1e8;
    
    vector<vector<int>> d(H, vector<int>(W, INF));
    deque<pair<int, int>> q;
    q.push_back({0, 0});
    d[0][0] = 1;
    
    int ans = 1;
    while(!q.empty()) {
        pair<int, int> cur = q.front();
        int y = cur.first;
        int x = cur.second;
        ans = max(ans, d[y][x]);
        q.pop_front();
        
        
        for(int k = 0; k < 4; k++) {
            int ny = y + dy[k];
            int nx = x + dx[k];
            
            if(ny < 0 || ny >= H || nx < 0 || nx >= W) continue;
            if(m[ny][nx] == '.') continue;
            
            int w = (m[y][x] != m[ny][nx]);
            if(d[ny][nx] > d[y][x] + w) {
                d[ny][nx] = d[y][x] + w;
                if(w) q.push_back({ny, nx});
                else q.push_front({ny, nx});
            }
        }
    } 
    
    cout << ans << '\n';
}

// ........ RRR..... FFR.....
// ........ ..RRR... .FRRR...
// ........ ..R..... .FFFFF..
// ........ ..RRRR.R ..RRRFFR
// ........ .....RRR .....FFF

// i had a greedy that always would work but the 0/1 bfs is just too clean

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 1740 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 0 ms 332 KB Output is correct
4 Correct 6 ms 1484 KB Output is correct
5 Correct 2 ms 716 KB Output is correct
6 Correct 0 ms 204 KB Output is correct
7 Correct 0 ms 204 KB Output is correct
8 Correct 1 ms 332 KB Output is correct
9 Correct 1 ms 332 KB Output is correct
10 Correct 2 ms 716 KB Output is correct
11 Correct 2 ms 588 KB Output is correct
12 Correct 4 ms 844 KB Output is correct
13 Correct 2 ms 716 KB Output is correct
14 Correct 2 ms 840 KB Output is correct
15 Correct 12 ms 1860 KB Output is correct
16 Correct 11 ms 1740 KB Output is correct
17 Correct 7 ms 1740 KB Output is correct
18 Correct 8 ms 1484 KB Output is correct

Subtask #2
70.0 / 70.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 716 KB Output is correct
2 Correct 36 ms 8524 KB Output is correct
3 Correct 195 ms 81640 KB Output is correct
4 Correct 60 ms 19444 KB Output is correct
5 Correct 142 ms 46216 KB Output is correct
6 Correct 708 ms 95348 KB Output is correct
7 Correct 2 ms 716 KB Output is correct
8 Correct 2 ms 716 KB Output is correct
9 Correct 2 ms 588 KB Output is correct
10 Correct 1 ms 460 KB Output is correct
11 Correct 1 ms 716 KB Output is correct
12 Correct 2 ms 460 KB Output is correct
13 Correct 41 ms 8524 KB Output is correct
14 Correct 21 ms 5256 KB Output is correct
15 Correct 15 ms 5724 KB Output is correct
16 Correct 19 ms 3936 KB Output is correct
17 Correct 100 ms 20900 KB Output is correct
18 Correct 60 ms 20708 KB Output is correct
19 Correct 54 ms 19336 KB Output is correct
20 Correct 54 ms 17908 KB Output is correct
21 Correct 115 ms 47756 KB Output is correct
22 Correct 159 ms 46152 KB Output is correct
23 Correct 195 ms 39860 KB Output is correct
24 Correct 113 ms 46620 KB Output is correct
25 Correct 359 ms 81596 KB Output is correct
26 Correct 760 ms 112816 KB Output is correct
27 Correct 665 ms 103268 KB Output is correct
28 Correct 731 ms 95408 KB Output is correct
29 Correct 705 ms 92520 KB Output is correct
30 Correct 737 ms 96324 KB Output is correct
31 Correct 538 ms 52888 KB Output is correct
32 Correct 674 ms 97940 KB Output is correct