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Submission #500085

# Submission time Handle Problem Language Result Execution time Memory
500085 2021-12-30T10:06:37 Z Nartifact Mecho (IOI09_mecho) C++17
95 / 100
 220 ms 4356 KB 
#include <bits/stdc++.h>
using namespace std;

#define forinc(i,a,b) for(int i=a;i<=b;++i)
#define fordec(i,a,b) for(int i=a;i>=b;--i)
#define pb push_back
#define eb emplace_back
#define pii pair <int,int>
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int N = 802, inf = 2e9;
const int H[] = {1, 0, -1, 0};
const int C[] = {0, 1, 0, -1};
int n, s;
char a[N][N];
int t[N][N];
bool cx[N][N];
pii sta, fin;

bool valid (const int& x, const int& y)
{
    return x && y && x <= n && y <= n
          && a[x][y] != 'T';
}

struct adt {int x, y, step;};

bool ok (const int& tg)
{
    queue <adt> q;
    memset(cx, 0, sizeof cx);
    q.push({sta.fi, sta.se, 0});
    cx[sta.fi][sta.se] = 1;
    while(q.size()) {
        auto tmp = q.front(); q.pop();
        if(tmp.x == fin.fi && tmp.y == fin.se) return 1;
        forinc(i,0,3) {
            int nh = tmp.x + H[i];
            int nc = tmp.y + C[i];
            if(valid(nh, nc) && !cx[nh][nc] && (tmp.step + 1) / s < t[nh][nc] - tg) {
                q.push({nh, nc, tmp.step + 1});
                cx[nh][nc] = 1;
            }
        }
    }
    return 0;
}

void solve ()
{
    queue <pii> q;
    forinc(i,1,n) forinc(j,1,n) {
        t[i][j] = inf;
        if(a[i][j] == 'H') {
            q.push({i, j});
            t[i][j] = 0;
        }
        else if(a[i][j] == 'M') sta = {i, j};
        else if(a[i][j] == 'D') fin = {i, j};
    }

    // bfs bee
    while(q.size()) {
        auto x = q.front(); q.pop();
        forinc(i,0,3) {
            int nh = x.fi + H[i];
            int nc = x.se + C[i];
            if(valid(nh, nc) && t[nh][nc] > t[x.fi][x.se] + 1) {
                t[nh][nc] = t[x.fi][x.se] + 1;
                q.push({nh, nc});
            }
        }
    }
	t[fin.fi][fin.se] = inf;
    // binary search
    int l = 0, r = t[sta.fi][sta.se] - 1, ans = -1;
    while(l <= r) {
        int mid = l + r >> 1;
        if(ok(mid)) {
            ans = mid;
            l = mid + 1;
        }
        else r = mid - 1;
    }
    cout << ans;
}

void read ()
{
    cin >> n >> s;
    forinc(i,1,n) forinc(j,1,n)
        cin >> a[i][j];
    solve();
}

main ()
{
	#define task "ioi09_mecho"
	cin.tie(0) -> sync_with_stdio(0);
	if(fopen (task ".inp", "r")) {
		freopen (task ".inp", "r", stdin);
		freopen (task ".out", "w", stdout);
	}
    read();
	return 0;
}

Compilation message

mecho.cpp: In function 'void solve()':
mecho.cpp:82:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   82 |         int mid = l + r >> 1;
      |                   ~~^~~
mecho.cpp: At global scope:
mecho.cpp:100:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  100 | main ()
      | ^~~~
mecho.cpp: In function 'int main()':
mecho.cpp:105:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  105 |   freopen (task ".inp", "r", stdin);
      |   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
mecho.cpp:106:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  106 |   freopen (task ".out", "w", stdout);
      |   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
95.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 972 KB Output is correct
2 Correct 1 ms 972 KB Output is correct
3 Correct 1 ms 972 KB Output is correct
4 Correct 1 ms 972 KB Output is correct
5 Correct 1 ms 972 KB Output is correct
6 Correct 1 ms 972 KB Output is correct
7 Correct 82 ms 4188 KB Output is correct
8 Correct 1 ms 972 KB Output is correct
9 Correct 1 ms 972 KB Output is correct
10 Correct 1 ms 984 KB Output is correct
11 Correct 1 ms 1024 KB Output is correct
12 Incorrect 1 ms 1100 KB Output isn't correct
13 Correct 1 ms 1100 KB Output is correct
14 Correct 2 ms 1100 KB Output is correct
15 Correct 1 ms 972 KB Output is correct
16 Correct 1 ms 972 KB Output is correct
17 Correct 1 ms 1052 KB Output is correct
18 Correct 1 ms 972 KB Output is correct
19 Correct 1 ms 972 KB Output is correct
20 Correct 1 ms 972 KB Output is correct
21 Correct 1 ms 1100 KB Output is correct
22 Correct 1 ms 1100 KB Output is correct
23 Correct 1 ms 1100 KB Output is correct
24 Correct 1 ms 1100 KB Output is correct
25 Correct 1 ms 1100 KB Output is correct
26 Correct 1 ms 1100 KB Output is correct
27 Correct 1 ms 1100 KB Output is correct
28 Correct 1 ms 1100 KB Output is correct
29 Correct 1 ms 1228 KB Output is correct
30 Correct 1 ms 1228 KB Output is correct
31 Correct 2 ms 1228 KB Output is correct
32 Correct 1 ms 1256 KB Output is correct
33 Correct 4 ms 2240 KB Output is correct
34 Correct 4 ms 2256 KB Output is correct
35 Correct 20 ms 2336 KB Output is correct
36 Correct 5 ms 2508 KB Output is correct
37 Correct 6 ms 2508 KB Output is correct
38 Correct 26 ms 2508 KB Output is correct
39 Correct 7 ms 2692 KB Output is correct
40 Correct 10 ms 2604 KB Output is correct
41 Correct 49 ms 2728 KB Output is correct
42 Correct 8 ms 2824 KB Output is correct
43 Correct 8 ms 2892 KB Output is correct
44 Correct 39 ms 2892 KB Output is correct
45 Correct 12 ms 2992 KB Output is correct
46 Correct 16 ms 2992 KB Output is correct
47 Correct 65 ms 3100 KB Output is correct
48 Correct 15 ms 3188 KB Output is correct
49 Correct 11 ms 3192 KB Output is correct
50 Correct 62 ms 3228 KB Output is correct
51 Correct 11 ms 3388 KB Output is correct
52 Correct 13 ms 3404 KB Output is correct
53 Correct 71 ms 3492 KB Output is correct
54 Correct 18 ms 3656 KB Output is correct
55 Correct 13 ms 3696 KB Output is correct
56 Correct 122 ms 3688 KB Output is correct
57 Correct 16 ms 3900 KB Output is correct
58 Correct 16 ms 3780 KB Output is correct
59 Correct 129 ms 3896 KB Output is correct
60 Correct 17 ms 3976 KB Output is correct
61 Correct 17 ms 3972 KB Output is correct
62 Correct 129 ms 4088 KB Output is correct
63 Correct 131 ms 4072 KB Output is correct
64 Correct 220 ms 4072 KB Output is correct
65 Correct 192 ms 3952 KB Output is correct
66 Correct 143 ms 4080 KB Output is correct
67 Correct 143 ms 4072 KB Output is correct
68 Correct 61 ms 3992 KB Output is correct
69 Correct 48 ms 3980 KB Output is correct
70 Correct 44 ms 4100 KB Output is correct
71 Correct 37 ms 4100 KB Output is correct
72 Correct 37 ms 3984 KB Output is correct
73 Correct 48 ms 4260 KB Output is correct
74 Correct 85 ms 4356 KB Output is correct
75 Correct 66 ms 4348 KB Output is correct
76 Correct 67 ms 4356 KB Output is correct
77 Correct 74 ms 4240 KB Output is correct
78 Correct 104 ms 4320 KB Output is correct
79 Correct 62 ms 4224 KB Output is correct
80 Correct 75 ms 4320 KB Output is correct
81 Correct 86 ms 4324 KB Output is correct
82 Correct 70 ms 4320 KB Output is correct
83 Correct 98 ms 4184 KB Output is correct
84 Correct 94 ms 4284 KB Output is correct
85 Correct 84 ms 4284 KB Output is correct
86 Correct 100 ms 4288 KB Output is correct
87 Correct 82 ms 4168 KB Output is correct
88 Correct 104 ms 4232 KB Output is correct
89 Correct 106 ms 4112 KB Output is correct
90 Correct 107 ms 4244 KB Output is correct
91 Correct 92 ms 4112 KB Output is correct
92 Correct 100 ms 4128 KB Output is correct