oj.uz

Submission #547343

# Submission time Handle Problem Language Result Execution time Memory
547343 2022-04-10T13:24:26 Z pancankes Mecho (IOI09_mecho) C++17
38 / 100
 218 ms 11724 KB 
#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <cmath>
using namespace std;
#define int long long
const int INF=1e18;
const int MAXN=801;

int n,s,ans=0;
string grid[MAXN];
int bee[MAXN][MAXN],dist[MAXN][MAXN];
vector<pair<int,int>> hives;
pair<int,int> start,dest;

int dx[4]{1, -1, 0, 0}, dy[4]{0, 0, 1, -1};
bool inside(int x, int y) {
	return (x > -1 && x < n && y > -1 && y < n && grid[x][y] != 'T');
}

void setIO(string name="") { 
    ios_base::sync_with_stdio(0); cin.tie(0); 
    if (!name.empty()) {
        freopen((name+".in").c_str(), "r", stdin); 
        freopen((name+".out").c_str(), "w", stdout);
    }
}

// check if after eating for t seconds,
// is it possible to reach the destination
bool check(int t)
{
    for (int i=0; i<n; i++)
        for (int j=0; j<n; j++)
            dist[i][j]=-1;
    queue<pair<int,int>>q;
    q.push(start);
    dist[start.first][start.second]=0;
    while (!q.empty())
    {
        pair<int,int> c=q.front();
        q.pop();

        for (int i=0; i<4; i++)
        {
            int x=c.first+dx[i],y=c.second+dy[i];
            // if i can usually get there in 7 step
            // taking 2 steps a minute i can get there in ceil(7/2) steps
            if (inside(x,y)&&dist[x][y]==-1&&(bee[x][y]-t)>=ceil((double)(dist[c.first][c.second]+1)/(double)s))
            {
                dist[x][y]=dist[c.first][c.second]+1;
                q.push({x,y});
            }
        }
    }
    // cout << t << endl;
    // for (int i=0; i<n; i++) {for (int j=0; j<n; j++) cout << dist[i][j] << " "; cout << endl;}
    if (dist[dest.first][dest.second]!=-1) return true;
    else return false;
}

int32_t main()
{
    cin >> n >> s;
    for (int i=0; i<n; i++) cin >> grid[i];
    for (int i=0; i<n; i++)
        for (int j=0; j<n; j++)
        {
            if (grid[i][j]=='M') start={i,j};
            if (grid[i][j]=='D') dest={i,j};
            if (grid[i][j]=='H') hives.push_back({i,j});
            bee[i][j]=INF;
        }
    // multisource bfs to find the distances of cells from hive
    queue<pair<int,int>> q;
    for (int i=0; i<hives.size(); i++) {
        q.push(hives[i]);
        bee[hives[i].first][hives[i].second]=0;
    }
    while (!q.empty())
    {
        pair<int,int> c=q.front();
        q.pop();
        for (int i=0; i<4; i++)
        {
            int x=c.first+dx[i],y=c.second+dy[i];
            if (inside(x,y)&&grid[x][y]!='D'&&bee[x][y]==INF)
            {
                bee[x][y]=bee[c.first][c.second]+1;
                q.push({x,y});
            }
        }
    }
    //for (int i=0; i<n; i++) {for (int j=0; j<n; j++) cout << bee[i][j] << " "; cout << endl;} cout << endl;
    int lo=0,hi=2000;
    while (lo<=hi)
    {
        int mid=lo+(hi-lo)/2;
        // cout << mid << endl;
        if (check(mid))
        {
            ans=max(ans,mid);
            lo=mid+1;
        }
        else hi=mid-1;
    }
    if (!check(0)) cout << -1 << endl;
    else cout << ans << endl;
}

Compilation message

mecho.cpp: In function 'int32_t main()':
mecho.cpp:79:20: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   79 |     for (int i=0; i<hives.size(); i++) {
      |                   ~^~~~~~~~~~~~~
mecho.cpp: In function 'void setIO(std::string)':
mecho.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         freopen((name+".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mecho.cpp:28:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |         freopen((name+".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
38.0 / 100.0

# Verdict Execution time Memory Grader output
1 Incorrect 0 ms 340 KB Output isn't correct
2 Incorrect 0 ms 340 KB Output isn't correct
3 Incorrect 0 ms 340 KB Output isn't correct
4 Incorrect 0 ms 340 KB Output isn't correct
5 Correct 0 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 108 ms 11260 KB Output is correct
8 Incorrect 0 ms 340 KB Output isn't correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Incorrect 1 ms 852 KB Output isn't correct
13 Incorrect 1 ms 724 KB Output isn't correct
14 Correct 1 ms 852 KB Output is correct
15 Incorrect 0 ms 468 KB Output isn't correct
16 Correct 0 ms 468 KB Output is correct
17 Incorrect 0 ms 468 KB Output isn't correct
18 Correct 1 ms 468 KB Output is correct
19 Incorrect 1 ms 596 KB Output isn't correct
20 Correct 1 ms 596 KB Output is correct
21 Incorrect 1 ms 596 KB Output isn't correct
22 Correct 1 ms 596 KB Output is correct
23 Incorrect 1 ms 724 KB Output isn't correct
24 Correct 1 ms 724 KB Output is correct
25 Incorrect 1 ms 852 KB Output isn't correct
26 Correct 1 ms 852 KB Output is correct
27 Incorrect 1 ms 852 KB Output isn't correct
28 Correct 1 ms 852 KB Output is correct
29 Incorrect 1 ms 980 KB Output isn't correct
30 Correct 1 ms 980 KB Output is correct
31 Incorrect 1 ms 980 KB Output isn't correct
32 Correct 1 ms 980 KB Output is correct
33 Incorrect 19 ms 4820 KB Output isn't correct
34 Incorrect 21 ms 4844 KB Output isn't correct
35 Correct 26 ms 4908 KB Output is correct
36 Incorrect 24 ms 5548 KB Output isn't correct
37 Incorrect 28 ms 5460 KB Output isn't correct
38 Correct 35 ms 5460 KB Output is correct
39 Incorrect 32 ms 6100 KB Output isn't correct
40 Incorrect 45 ms 6096 KB Output isn't correct
41 Correct 45 ms 6100 KB Output is correct
42 Incorrect 36 ms 7020 KB Output isn't correct
43 Incorrect 45 ms 7028 KB Output isn't correct
44 Correct 51 ms 6996 KB Output is correct
45 Incorrect 46 ms 7740 KB Output isn't correct
46 Incorrect 55 ms 7728 KB Output isn't correct
47 Correct 85 ms 7764 KB Output is correct
48 Incorrect 58 ms 8404 KB Output isn't correct
49 Incorrect 69 ms 8416 KB Output isn't correct
50 Correct 81 ms 8404 KB Output is correct
51 Incorrect 68 ms 9088 KB Output isn't correct
52 Incorrect 107 ms 9044 KB Output isn't correct
53 Correct 101 ms 9104 KB Output is correct
54 Incorrect 73 ms 9760 KB Output isn't correct
55 Incorrect 83 ms 9748 KB Output isn't correct
56 Correct 118 ms 9768 KB Output is correct
57 Incorrect 84 ms 10324 KB Output isn't correct
58 Incorrect 102 ms 10360 KB Output isn't correct
59 Correct 139 ms 10376 KB Output is correct
60 Incorrect 91 ms 11104 KB Output isn't correct
61 Incorrect 115 ms 11220 KB Output isn't correct
62 Correct 166 ms 11124 KB Output is correct
63 Correct 144 ms 11144 KB Output is correct
64 Correct 218 ms 11084 KB Output is correct
65 Correct 196 ms 11124 KB Output is correct
66 Incorrect 169 ms 11128 KB Output isn't correct
67 Correct 130 ms 11116 KB Output is correct
68 Correct 64 ms 11156 KB Output is correct
69 Correct 62 ms 11184 KB Output is correct
70 Correct 56 ms 11144 KB Output is correct
71 Correct 50 ms 11184 KB Output is correct
72 Incorrect 49 ms 11308 KB Output isn't correct
73 Incorrect 48 ms 11604 KB Output isn't correct
74 Correct 86 ms 11688 KB Output is correct
75 Correct 83 ms 11688 KB Output is correct
76 Correct 82 ms 11712 KB Output is correct
77 Correct 78 ms 11712 KB Output is correct
78 Correct 85 ms 11724 KB Output is correct
79 Correct 92 ms 11652 KB Output is correct
80 Correct 88 ms 11604 KB Output is correct
81 Correct 85 ms 11652 KB Output is correct
82 Correct 88 ms 11644 KB Output is correct
83 Correct 96 ms 11464 KB Output is correct
84 Correct 103 ms 11516 KB Output is correct
85 Correct 103 ms 11556 KB Output is correct
86 Correct 94 ms 11552 KB Output is correct
87 Correct 94 ms 11468 KB Output is correct
88 Correct 104 ms 11448 KB Output is correct
89 Correct 113 ms 11572 KB Output is correct
90 Correct 107 ms 11440 KB Output is correct
91 Correct 104 ms 11376 KB Output is correct
92 Correct 111 ms 11340 KB Output is correct