oj.uz

답안 #547379

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
547379 2022-04-10T14:39:49 Z pancankes Mecho (IOI09_mecho) C++17
57 / 100
 218 ms 11720 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)>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;}
    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

# 결과 실행 시간 메모리 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 0 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 109 ms 11224 KB Output is correct
8 Correct 0 ms 340 KB Output is correct
9 Correct 0 ms 340 KB Output is correct
10 Correct 0 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 Correct 0 ms 468 KB Output is correct
16 Correct 0 ms 468 KB Output is correct
17 Correct 1 ms 468 KB Output is correct
18 Correct 0 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 Incorrect 1 ms 852 KB Output isn't correct
28 Correct 1 ms 852 KB Output is correct
29 Incorrect 1 ms 924 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 17 ms 4892 KB Output isn't correct
34 Incorrect 19 ms 4896 KB Output isn't correct
35 Correct 22 ms 4900 KB Output is correct
36 Incorrect 21 ms 5448 KB Output isn't correct
37 Incorrect 25 ms 5552 KB Output isn't correct
38 Correct 30 ms 5536 KB Output is correct
39 Incorrect 25 ms 6100 KB Output isn't correct
40 Incorrect 31 ms 6100 KB Output isn't correct
41 Correct 46 ms 6184 KB Output is correct
42 Incorrect 33 ms 6996 KB Output isn't correct
43 Incorrect 40 ms 6996 KB Output isn't correct
44 Correct 47 ms 7076 KB Output is correct
45 Incorrect 42 ms 7644 KB Output isn't correct
46 Incorrect 46 ms 7736 KB Output isn't correct
47 Correct 65 ms 7648 KB Output is correct
48 Incorrect 50 ms 8416 KB Output isn't correct
49 Incorrect 63 ms 8380 KB Output isn't correct
50 Correct 102 ms 8424 KB Output is correct
51 Incorrect 65 ms 9088 KB Output isn't correct
52 Incorrect 69 ms 9084 KB Output isn't correct
53 Correct 97 ms 9112 KB Output is correct
54 Incorrect 68 ms 9676 KB Output isn't correct
55 Incorrect 76 ms 9692 KB Output isn't correct
56 Correct 108 ms 9776 KB Output is correct
57 Incorrect 71 ms 10360 KB Output isn't correct
58 Incorrect 88 ms 10356 KB Output isn't correct
59 Correct 125 ms 10452 KB Output is correct
60 Incorrect 84 ms 11220 KB Output isn't correct
61 Incorrect 100 ms 11112 KB Output isn't correct
62 Correct 141 ms 11112 KB Output is correct
63 Correct 132 ms 11032 KB Output is correct
64 Correct 218 ms 11124 KB Output is correct
65 Correct 215 ms 11220 KB Output is correct
66 Correct 161 ms 11124 KB Output is correct
67 Correct 133 ms 11100 KB Output is correct
68 Correct 66 ms 11176 KB Output is correct
69 Correct 65 ms 11084 KB Output is correct
70 Correct 64 ms 11176 KB Output is correct
71 Correct 56 ms 11172 KB Output is correct
72 Incorrect 47 ms 11084 KB Output isn't correct
73 Incorrect 46 ms 11692 KB Output isn't correct
74 Correct 79 ms 11556 KB Output is correct
75 Correct 79 ms 11720 KB Output is correct
76 Correct 69 ms 11632 KB Output is correct
77 Correct 70 ms 11704 KB Output is correct
78 Correct 79 ms 11612 KB Output is correct
79 Correct 74 ms 11640 KB Output is correct
80 Correct 72 ms 11644 KB Output is correct
81 Correct 80 ms 11652 KB Output is correct
82 Correct 74 ms 11596 KB Output is correct
83 Correct 96 ms 11556 KB Output is correct
84 Correct 92 ms 11540 KB Output is correct
85 Correct 84 ms 11640 KB Output is correct
86 Correct 93 ms 11552 KB Output is correct
87 Correct 86 ms 11548 KB Output is correct
88 Correct 92 ms 11456 KB Output is correct
89 Correct 103 ms 11456 KB Output is correct
90 Correct 96 ms 11432 KB Output is correct
91 Correct 99 ms 11456 KB Output is correct
92 Correct 96 ms 11460 KB Output is correct