oj.uz

Submission #547626

# Submission time Handle Problem Language Result Execution time Memory
547626 2022-04-11T06:18:16 Z pancankes Mecho (IOI09_mecho) C++17
84 / 100
 229 ms 11800 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(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;}
    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=n*n;
    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
84.0 / 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 0 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 412 KB Output is correct
7 Correct 130 ms 11232 KB Output is correct
8 Correct 0 ms 340 KB Output is correct
9 Correct 0 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 1 ms 852 KB Output is correct
15 Correct 1 ms 468 KB Output is correct
16 Correct 0 ms 468 KB Output is correct
17 Correct 1 ms 508 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 596 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 Correct 1 ms 852 KB Output is correct
28 Correct 1 ms 852 KB Output is correct
29 Correct 1 ms 980 KB Output is correct
30 Correct 1 ms 980 KB Output is correct
31 Correct 1 ms 980 KB Output is correct
32 Correct 1 ms 980 KB Output is correct
33 Correct 10 ms 4820 KB Output is correct
34 Correct 9 ms 4820 KB Output is correct
35 Correct 25 ms 4904 KB Output is correct
36 Correct 11 ms 5460 KB Output is correct
37 Correct 11 ms 5460 KB Output is correct
38 Correct 29 ms 5536 KB Output is correct
39 Correct 12 ms 6100 KB Output is correct
40 Correct 14 ms 6104 KB Output is correct
41 Correct 41 ms 6100 KB Output is correct
42 Correct 16 ms 7088 KB Output is correct
43 Correct 17 ms 6996 KB Output is correct
44 Correct 49 ms 7052 KB Output is correct
45 Correct 19 ms 7712 KB Output is correct
46 Correct 20 ms 7648 KB Output is correct
47 Correct 61 ms 7764 KB Output is correct
48 Correct 21 ms 8432 KB Output is correct
49 Correct 24 ms 8424 KB Output is correct
50 Correct 71 ms 8364 KB Output is correct
51 Correct 27 ms 9092 KB Output is correct
52 Correct 28 ms 8996 KB Output is correct
53 Correct 94 ms 9104 KB Output is correct
54 Correct 33 ms 9676 KB Output is correct
55 Correct 31 ms 9684 KB Output is correct
56 Correct 133 ms 9776 KB Output is correct
57 Correct 33 ms 10452 KB Output is correct
58 Correct 36 ms 10452 KB Output is correct
59 Correct 122 ms 10372 KB Output is correct
60 Correct 37 ms 11112 KB Output is correct
61 Correct 41 ms 11204 KB Output is correct
62 Correct 144 ms 11124 KB Output is correct
63 Correct 126 ms 11108 KB Output is correct
64 Correct 229 ms 11124 KB Output is correct
65 Correct 175 ms 11124 KB Output is correct
66 Correct 146 ms 11128 KB Output is correct
67 Correct 136 ms 11128 KB Output is correct
68 Correct 64 ms 11176 KB Output is correct
69 Correct 65 ms 11184 KB Output is correct
70 Correct 52 ms 11140 KB Output is correct
71 Correct 57 ms 11180 KB Output is correct
72 Incorrect 53 ms 11092 KB Output isn't correct
73 Incorrect 54 ms 11704 KB Output isn't correct
74 Correct 82 ms 11800 KB Output is correct
75 Correct 78 ms 11716 KB Output is correct
76 Correct 78 ms 11732 KB Output is correct
77 Correct 75 ms 11692 KB Output is correct
78 Correct 83 ms 11648 KB Output is correct
79 Correct 73 ms 11628 KB Output is correct
80 Correct 74 ms 11644 KB Output is correct
81 Correct 84 ms 11600 KB Output is correct
82 Correct 82 ms 11624 KB Output is correct
83 Correct 94 ms 11468 KB Output is correct
84 Correct 90 ms 11552 KB Output is correct
85 Correct 87 ms 11536 KB Output is correct
86 Correct 89 ms 11468 KB Output is correct
87 Correct 86 ms 11552 KB Output is correct
88 Correct 92 ms 11448 KB Output is correct
89 Correct 105 ms 11436 KB Output is correct
90 Correct 96 ms 11392 KB Output is correct
91 Correct 104 ms 11424 KB Output is correct
92 Correct 104 ms 11456 KB Output is correct