oj.uz

Submission #547624

# Submission time Handle Problem Language Result Execution time Memory
547624 2022-04-11T06:16:11 Z pancankes Mecho (IOI09_mecho) C++17
57 / 100
 224 ms 12372 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' && grid[x][y]!='D');
}

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]=INF;
    queue<pair<int,int>>q;
    if (bee[start.first][start.second]>=t) 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]==INF&&(bee[x][y]-t)>(dist[c.first][c.second]+1)/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;}
    bool reached=false;
    for (int i=0; i<4; i++)
    {
        int x=dest.first+dx[i],y=dest.second+dy[i];
        if (inside(x,y)&&dist[x][y]!=INF)
            reached=true;
    }
    return reached;
}

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:85:20: 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]
   85 |     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
57.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 1 ms 336 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 114 ms 11972 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 460 KB Output is correct
10 Correct 1 ms 336 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 Correct 1 ms 464 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 596 KB Output is correct
20 Correct 1 ms 596 KB Output is correct
21 Correct 1 ms 596 KB Output is correct
22 Correct 1 ms 608 KB Output is correct
23 Correct 1 ms 724 KB Output is correct
24 Correct 1 ms 724 KB Output is correct
25 Correct 1 ms 852 KB Output is 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 976 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 16 ms 4956 KB Output isn't correct
34 Incorrect 20 ms 4948 KB Output isn't correct
35 Correct 24 ms 4948 KB Output is correct
36 Incorrect 20 ms 5704 KB Output isn't correct
37 Incorrect 22 ms 5708 KB Output isn't correct
38 Correct 29 ms 5676 KB Output is correct
39 Incorrect 23 ms 6348 KB Output isn't correct
40 Incorrect 29 ms 6356 KB Output isn't correct
41 Correct 36 ms 6356 KB Output is correct
42 Incorrect 34 ms 7252 KB Output isn't correct
43 Incorrect 36 ms 7320 KB Output isn't correct
44 Correct 48 ms 7328 KB Output is correct
45 Incorrect 37 ms 8056 KB Output isn't correct
46 Incorrect 44 ms 8032 KB Output isn't correct
47 Correct 60 ms 8048 KB Output is correct
48 Incorrect 42 ms 8780 KB Output isn't correct
49 Incorrect 51 ms 8764 KB Output isn't correct
50 Correct 74 ms 8776 KB Output is correct
51 Incorrect 49 ms 9428 KB Output isn't correct
52 Incorrect 61 ms 9544 KB Output isn't correct
53 Correct 88 ms 9516 KB Output is correct
54 Incorrect 59 ms 10240 KB Output isn't correct
55 Incorrect 70 ms 10248 KB Output isn't correct
56 Correct 102 ms 10224 KB Output is correct
57 Incorrect 66 ms 10984 KB Output isn't correct
58 Incorrect 80 ms 10984 KB Output isn't correct
59 Correct 162 ms 11000 KB Output is correct
60 Incorrect 72 ms 11724 KB Output isn't correct
61 Incorrect 97 ms 11740 KB Output isn't correct
62 Correct 143 ms 11752 KB Output is correct
63 Correct 134 ms 11860 KB Output is correct
64 Correct 224 ms 11852 KB Output is correct
65 Correct 194 ms 11708 KB Output is correct
66 Correct 163 ms 11844 KB Output is correct
67 Correct 127 ms 11736 KB Output is correct
68 Correct 63 ms 11812 KB Output is correct
69 Correct 61 ms 11700 KB Output is correct
70 Correct 56 ms 11728 KB Output is correct
71 Correct 51 ms 11812 KB Output is correct
72 Incorrect 48 ms 11808 KB Output isn't correct
73 Incorrect 54 ms 12304 KB Output isn't correct
74 Correct 80 ms 12288 KB Output is correct
75 Correct 76 ms 12220 KB Output is correct
76 Correct 69 ms 12284 KB Output is correct
77 Correct 75 ms 12300 KB Output is correct
78 Correct 79 ms 12372 KB Output is correct
79 Correct 75 ms 12180 KB Output is correct
80 Correct 70 ms 12272 KB Output is correct
81 Correct 81 ms 12240 KB Output is correct
82 Correct 75 ms 12208 KB Output is correct
83 Correct 95 ms 12188 KB Output is correct
84 Correct 93 ms 12140 KB Output is correct
85 Correct 80 ms 12188 KB Output is correct
86 Correct 86 ms 12144 KB Output is correct
87 Correct 86 ms 12192 KB Output is correct
88 Correct 97 ms 12016 KB Output is correct
89 Correct 109 ms 12068 KB Output is correct
90 Correct 136 ms 12088 KB Output is correct
91 Correct 104 ms 12084 KB Output is correct
92 Correct 100 ms 12080 KB Output is correct