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Submission #550474

# Submission time Handle Problem Language Result Execution time Memory
550474 2022-04-18T09:15:08 Z Jomnoi Mecho (IOI09_mecho) C++17
100 / 100
 182 ms 6332 KB 
#include <bits/stdc++.h>
#define DEBUG false
using namespace std;

const int MAX_N = 810;
const int INF = 1e9 + 7;
const int d[4][2] = {{1, 0}, {0, 1}, {-1, 0}, {0, -1}};

char s[MAX_N][MAX_N];
int db[MAX_N][MAX_N], dm[MAX_N][MAX_N];

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int N, S;
    cin >> N >> S;
    for(int i = 1; i <= N; i++) {
        cin >> (s[i] + 1);
    }

    int sx, sy, ex, ey;
    queue <pair <int, int>> q;
    for(int i = 1; i <= N; i++) {
        for(int j = 1; j <= N; j++) {
            db[i][j] = INF;
            if(s[i][j] == 'H') {
                db[i][j] = 0;
                q.emplace(i, j);
            }
            else if(s[i][j] == 'M') {
                sx = i, sy = j;
            }
            else if(s[i][j] == 'D') {
                ex = i, ey = j;
            }
        }    
    }
    while(!q.empty()) {
        auto [ux, uy] = q.front();
        q.pop();

        for(int i = 0; i < 4; i++) {
            int vx = ux + d[i][0], vy = uy + d[i][1];
            if(vx < 1 or vx > N or vy < 1 or vy > N or s[vx][vy] == 'T' or s[vx][vy] == 'D' or db[vx][vy] != INF) {
                continue;
            }

            db[vx][vy] = db[ux][uy] + 1;
            q.emplace(vx, vy);
        }
    }

    int l = 0, r = N * N, ans = -1;
    while(l <= r) {
        int mid = (l + r) / 2;

        for(int i = 1; i <= N; i++) {
            for(int j = 1; j <= N; j++) {
                dm[i][j] = INF;
            }
        }

        queue <pair <int, int>> q;
        if(db[sx][sy] > mid) {
            q.emplace(sx, sy);
            dm[sx][sy] = 0;
        }
        while(!q.empty()) {
            auto [ux, uy] = q.front();
            q.pop();

            for(int i = 0; i < 4; i++) {
                int vx = ux + d[i][0], vy = uy + d[i][1];
                if(vx < 1 or vx > N or vy < 1 or vy > N or s[vx][vy] == 'T' or dm[vx][vy] != INF) {
                    continue;
                }
                if((dm[ux][uy] + 1) / S >= db[vx][vy] - mid) {
                    continue;
                }

                dm[vx][vy] = dm[ux][uy] + 1;
                q.emplace(vx, vy);
            }
        }

        if(dm[ex][ey] == INF) {
            r = mid - 1;
        }
        else {
            l = mid + 1;
            ans = mid;
        }
    }
    cout << ans;
    return 0;
}

Compilation message

mecho.cpp: In function 'int main()':
mecho.cpp:85:21: warning: 'ey' may be used uninitialized in this function [-Wmaybe-uninitialized]
   85 |         if(dm[ex][ey] == INF) {
      |            ~~~~~~~~~^
mecho.cpp:85:21: warning: 'ex' may be used uninitialized in this function [-Wmaybe-uninitialized]

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 76 ms 6140 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 1 ms 724 KB Output is correct
13 Correct 1 ms 596 KB Output is correct
14 Correct 1 ms 724 KB Output is correct
15 Correct 1 ms 468 KB Output is correct
16 Correct 1 ms 468 KB Output is correct
17 Correct 1 ms 468 KB Output is correct
18 Correct 1 ms 468 KB Output is correct
19 Correct 1 ms 468 KB Output is correct
20 Correct 1 ms 468 KB Output is correct
21 Correct 1 ms 596 KB Output is correct
22 Correct 1 ms 596 KB Output is correct
23 Correct 1 ms 596 KB Output is correct
24 Correct 1 ms 596 KB Output is correct
25 Correct 1 ms 724 KB Output is correct
26 Correct 1 ms 724 KB Output is correct
27 Correct 1 ms 724 KB Output is correct
28 Correct 1 ms 724 KB Output is correct
29 Correct 1 ms 724 KB Output is correct
30 Correct 1 ms 724 KB Output is correct
31 Correct 1 ms 852 KB Output is correct
32 Correct 1 ms 852 KB Output is correct
33 Correct 4 ms 2772 KB Output is correct
34 Correct 6 ms 2840 KB Output is correct
35 Correct 19 ms 2752 KB Output is correct
36 Correct 5 ms 3156 KB Output is correct
37 Correct 7 ms 3156 KB Output is correct
38 Correct 27 ms 3156 KB Output is correct
39 Correct 7 ms 3540 KB Output is correct
40 Correct 9 ms 3540 KB Output is correct
41 Correct 38 ms 3540 KB Output is correct
42 Correct 8 ms 3796 KB Output is correct
43 Correct 12 ms 3852 KB Output is correct
44 Correct 42 ms 3892 KB Output is correct
45 Correct 10 ms 4180 KB Output is correct
46 Correct 12 ms 4180 KB Output is correct
47 Correct 57 ms 4252 KB Output is correct
48 Correct 11 ms 4564 KB Output is correct
49 Correct 17 ms 4620 KB Output is correct
50 Correct 61 ms 4564 KB Output is correct
51 Correct 13 ms 4976 KB Output is correct
52 Correct 17 ms 4972 KB Output is correct
53 Correct 75 ms 4976 KB Output is correct
54 Correct 16 ms 5204 KB Output is correct
55 Correct 18 ms 5280 KB Output is correct
56 Correct 97 ms 5312 KB Output is correct
57 Correct 18 ms 5612 KB Output is correct
58 Correct 22 ms 5616 KB Output is correct
59 Correct 109 ms 5620 KB Output is correct
60 Correct 19 ms 5972 KB Output is correct
61 Correct 23 ms 5932 KB Output is correct
62 Correct 121 ms 6028 KB Output is correct
63 Correct 107 ms 6092 KB Output is correct
64 Correct 182 ms 5972 KB Output is correct
65 Correct 132 ms 6024 KB Output is correct
66 Correct 119 ms 6044 KB Output is correct
67 Correct 121 ms 6060 KB Output is correct
68 Correct 49 ms 5960 KB Output is correct
69 Correct 41 ms 5972 KB Output is correct
70 Correct 33 ms 5968 KB Output is correct
71 Correct 38 ms 6056 KB Output is correct
72 Correct 31 ms 5972 KB Output is correct
73 Correct 46 ms 6332 KB Output is correct
74 Correct 56 ms 6228 KB Output is correct
75 Correct 70 ms 6296 KB Output is correct
76 Correct 53 ms 6220 KB Output is correct
77 Correct 54 ms 6216 KB Output is correct
78 Correct 76 ms 6188 KB Output is correct
79 Correct 53 ms 6272 KB Output is correct
80 Correct 64 ms 6280 KB Output is correct
81 Correct 61 ms 6292 KB Output is correct
82 Correct 53 ms 6228 KB Output is correct
83 Correct 69 ms 6232 KB Output is correct
84 Correct 72 ms 6148 KB Output is correct
85 Correct 77 ms 6228 KB Output is correct
86 Correct 68 ms 6240 KB Output is correct
87 Correct 66 ms 6232 KB Output is correct
88 Correct 68 ms 6100 KB Output is correct
89 Correct 74 ms 6188 KB Output is correct
90 Correct 99 ms 6100 KB Output is correct
91 Correct 102 ms 6088 KB Output is correct
92 Correct 82 ms 6180 KB Output is correct