oj.uz

Submission #547367

# Submission time Handle Problem Language Result Execution time Memory
547367 2022-04-10T14:16:01 Z pancankes Mecho (IOI09_mecho) C++17
38 / 100
 253 ms 11716 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]=INF;
    queue<pair<int,int>>q;
    if (bee[start.first][start.second]-t>=0) 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)>=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]!=INF) 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 1 ms 340 KB Output isn't correct
4 Incorrect 1 ms 340 KB Output isn't correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 0 ms 340 KB Output is correct
7 Correct 116 ms 11260 KB Output is correct
8 Incorrect 1 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 0 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 2 ms 852 KB Output is correct
15 Incorrect 0 ms 468 KB Output isn't correct
16 Correct 1 ms 468 KB Output is correct
17 Incorrect 1 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 21 ms 4896 KB Output isn't correct
34 Incorrect 23 ms 4892 KB Output isn't correct
35 Correct 27 ms 4908 KB Output is correct
36 Incorrect 28 ms 5436 KB Output isn't correct
37 Incorrect 36 ms 5460 KB Output isn't correct
38 Correct 52 ms 5460 KB Output is correct
39 Incorrect 31 ms 6196 KB Output isn't correct
40 Incorrect 38 ms 6116 KB Output isn't correct
41 Correct 55 ms 6188 KB Output is correct
42 Incorrect 40 ms 6996 KB Output isn't correct
43 Incorrect 51 ms 7064 KB Output isn't correct
44 Correct 65 ms 7028 KB Output is correct
45 Incorrect 61 ms 7636 KB Output isn't correct
46 Incorrect 61 ms 7688 KB Output isn't correct
47 Correct 73 ms 7768 KB Output is correct
48 Incorrect 54 ms 8336 KB Output isn't correct
49 Incorrect 66 ms 8388 KB Output isn't correct
50 Correct 103 ms 8424 KB Output is correct
51 Incorrect 66 ms 9092 KB Output isn't correct
52 Incorrect 79 ms 9008 KB Output isn't correct
53 Correct 113 ms 9100 KB Output is correct
54 Incorrect 76 ms 9684 KB Output isn't correct
55 Incorrect 87 ms 9760 KB Output isn't correct
56 Correct 127 ms 9776 KB Output is correct
57 Incorrect 86 ms 10428 KB Output isn't correct
58 Incorrect 107 ms 10428 KB Output isn't correct
59 Correct 162 ms 10448 KB Output is correct
60 Incorrect 96 ms 11112 KB Output isn't correct
61 Incorrect 119 ms 11028 KB Output isn't correct
62 Correct 177 ms 11124 KB Output is correct
63 Correct 151 ms 11124 KB Output is correct
64 Correct 253 ms 11124 KB Output is correct
65 Correct 212 ms 11124 KB Output is correct
66 Incorrect 181 ms 11132 KB Output isn't correct
67 Correct 141 ms 11104 KB Output is correct
68 Correct 82 ms 11164 KB Output is correct
69 Correct 66 ms 11156 KB Output is correct
70 Correct 62 ms 11084 KB Output is correct
71 Correct 55 ms 11180 KB Output is correct
72 Incorrect 57 ms 11092 KB Output isn't correct
73 Incorrect 57 ms 11696 KB Output isn't correct
74 Correct 100 ms 11688 KB Output is correct
75 Correct 96 ms 11716 KB Output is correct
76 Correct 89 ms 11704 KB Output is correct
77 Correct 90 ms 11716 KB Output is correct
78 Correct 94 ms 11628 KB Output is correct
79 Correct 107 ms 11636 KB Output is correct
80 Correct 85 ms 11644 KB Output is correct
81 Correct 95 ms 11652 KB Output is correct
82 Correct 90 ms 11640 KB Output is correct
83 Correct 124 ms 11560 KB Output is correct
84 Correct 117 ms 11468 KB Output is correct
85 Correct 97 ms 11556 KB Output is correct
86 Correct 115 ms 11536 KB Output is correct
87 Correct 93 ms 11556 KB Output is correct
88 Correct 98 ms 11452 KB Output is correct
89 Correct 116 ms 11452 KB Output is correct
90 Correct 104 ms 11400 KB Output is correct
91 Correct 109 ms 11340 KB Output is correct
92 Correct 99 ms 11452 KB Output is correct