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답안 #338596

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
338596 2020-12-23T13:17:42 Z blue Mecho (IOI09_mecho) C++11
84 / 100
 983 ms 8488 KB 
#include <iostream>
#include <vector>
#include <queue>
#include <set>
using namespace std;

/*
Mecho takes at most S steps per minute.
Bees spread every minute.

(*) Restatement:
Mecho takes at most 1 step every minute.
Bees spread at the end of every S'th minute.

For every location, compute the number of minutes before the location cannot be occupied anymore.
For trees and hives this number is zero.
Consider hives as -1
Consider
*/
int N, S;
int grid[800*800]; //the number of minutes before this location cannot be occupied anymore.
int mecho;
int home;
vector<int> edge;
vector<int> dist(800*800, 1e9);
//LOOKS GOOD

int INF = 1e9;

int binary_search(int a, int b)
{
    // cout << "____________________________\n binary search " << a << ' ' << b << '\n';
    int m = (a+b)/2+1;
    if(a == b) m = a;

    //cout << mecho << ' ' << dist[mecho] << ' ' << home << '\n';
    for(int i = 0; i < N*N; i++) dist[i] = INF;

    queue<int> tbv;
    dist[mecho] = m;
    tbv.push(mecho);


    int u;
    while(!tbv.empty())
    {
        u = tbv.front();
    //    cout << u << ' ' << dist[u] << '\n';
        tbv.pop();

        vector<int> edge; //check down
        edge.clear();
        if(u % N != 0) edge.push_back(u-1);
        if(u % N != N-1) edge.push_back(u+1);
        if(u >= N) edge.push_back(u-N);
        if(u < N*(N-1)) edge.push_back(u+N);

        for(int v: edge)
        {
            if(dist[v] != INF) continue;
            if(dist[u] + 1 >= grid[v]) continue;
            dist[v] = dist[u] + 1;
            tbv.push(v);
        }
    }

    if(a == b)
    {
        if(dist[home] == INF) return -1;
        else return a/S;
    }
    else
    {
        if(dist[home] == INF) return binary_search(a, m-1);
        else return binary_search(m, b);
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    char c;
    cin >> N >> S;

    for(int i = 0; i < N*N; i++)
    {
        cin >> c;
        if(c == 'T') grid[i] = 0;
        else if(c == 'G') grid[i] = INF;
        else if(c == 'M')
        {
            grid[i] = INF;
            mecho = i;
        }
        else if(c == 'D')
        {
            grid[i] = 0;
            home = i;
        }
        else grid[i] = -1;
    }

    vector<int> visit(N*N, 0);

    queue<int> tbv;

    for(int i = 0; i < N*N; i++)
    {
        if(grid[i] != -1) continue;
        grid[i] = 0;
        tbv.push(i);
        visit[i] = 1;
    }

    while(tbv.size() > 0)
    {
        int u = tbv.front();
        tbv.pop();

        edge.clear();
        if(u % N > 0) edge.push_back(u-1);
        if(u % N < N-1) edge.push_back(u+1);
        if(u >= N) edge.push_back(u-N);
        if(u < N*(N-1)) edge.push_back(u+N);

        for(int v: edge)
        {
            if(visit[v]) continue;
            if(grid[v] > grid[u] + S)
            {
                grid[v] = grid[u] + S;
                tbv.push(v);
            }
        }
    }

    grid[home] = INF;

    // for(int i = 0; i < N*N; i++)
    // {
    //     cout << grid[i] << ' ';
    //     if(i % N == N-1) cout << '\n';
    // }

    cout << binary_search(0, 2e9) << '\n';
}

Subtask #1
84.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2924 KB Output is correct
2 Correct 2 ms 2924 KB Output is correct
3 Correct 2 ms 2924 KB Output is correct
4 Correct 2 ms 2924 KB Output is correct
5 Correct 2 ms 2924 KB Output is correct
6 Correct 2 ms 2924 KB Output is correct
7 Correct 470 ms 8488 KB Output is correct
8 Correct 2 ms 2924 KB Output is correct
9 Correct 2 ms 2924 KB Output is correct
10 Correct 2 ms 2924 KB Output is correct
11 Correct 2 ms 2924 KB Output is correct
12 Incorrect 2 ms 2924 KB Output isn't correct
13 Incorrect 3 ms 2924 KB Output isn't correct
14 Correct 3 ms 2924 KB Output is correct
15 Correct 2 ms 2924 KB Output is correct
16 Correct 2 ms 2924 KB Output is correct
17 Correct 2 ms 2924 KB Output is correct
18 Correct 2 ms 2924 KB Output is correct
19 Correct 2 ms 2924 KB Output is correct
20 Correct 2 ms 2924 KB Output is correct
21 Correct 2 ms 2924 KB Output is correct
22 Correct 2 ms 2924 KB Output is correct
23 Correct 2 ms 2924 KB Output is correct
24 Correct 2 ms 2924 KB Output is correct
25 Correct 2 ms 2924 KB Output is correct
26 Correct 2 ms 2924 KB Output is correct
27 Correct 2 ms 2924 KB Output is correct
28 Correct 3 ms 2924 KB Output is correct
29 Correct 2 ms 2924 KB Output is correct
30 Correct 3 ms 2924 KB Output is correct
31 Correct 2 ms 2924 KB Output is correct
32 Correct 3 ms 2924 KB Output is correct
33 Correct 13 ms 3872 KB Output is correct
34 Correct 13 ms 3820 KB Output is correct
35 Correct 160 ms 3948 KB Output is correct
36 Correct 13 ms 4076 KB Output is correct
37 Correct 13 ms 4076 KB Output is correct
38 Correct 222 ms 4076 KB Output is correct
39 Correct 18 ms 4460 KB Output is correct
40 Correct 21 ms 4460 KB Output is correct
41 Correct 273 ms 4460 KB Output is correct
42 Correct 18 ms 4844 KB Output is correct
43 Correct 31 ms 4844 KB Output is correct
44 Correct 355 ms 5100 KB Output is correct
45 Correct 24 ms 5356 KB Output is correct
46 Correct 27 ms 5228 KB Output is correct
47 Correct 439 ms 5228 KB Output is correct
48 Correct 30 ms 5740 KB Output is correct
49 Correct 37 ms 5740 KB Output is correct
50 Correct 525 ms 5996 KB Output is correct
51 Correct 36 ms 6124 KB Output is correct
52 Correct 33 ms 6124 KB Output is correct
53 Correct 618 ms 6124 KB Output is correct
54 Correct 44 ms 6764 KB Output is correct
55 Correct 44 ms 6764 KB Output is correct
56 Correct 721 ms 6884 KB Output is correct
57 Correct 39 ms 7276 KB Output is correct
58 Correct 56 ms 7404 KB Output is correct
59 Correct 815 ms 7576 KB Output is correct
60 Correct 46 ms 7916 KB Output is correct
61 Correct 44 ms 8044 KB Output is correct
62 Correct 983 ms 7916 KB Output is correct
63 Correct 300 ms 7916 KB Output is correct
64 Correct 786 ms 8172 KB Output is correct
65 Correct 525 ms 8172 KB Output is correct
66 Correct 367 ms 8044 KB Output is correct
67 Correct 346 ms 8044 KB Output is correct
68 Correct 175 ms 7916 KB Output is correct
69 Correct 130 ms 7916 KB Output is correct
70 Correct 93 ms 7916 KB Output is correct
71 Correct 102 ms 7916 KB Output is correct
72 Incorrect 68 ms 7916 KB Output isn't correct
73 Incorrect 166 ms 8176 KB Output isn't correct
74 Correct 340 ms 8172 KB Output is correct
75 Correct 295 ms 8172 KB Output is correct
76 Correct 296 ms 8172 KB Output is correct
77 Correct 298 ms 8044 KB Output is correct
78 Correct 388 ms 8044 KB Output is correct
79 Correct 360 ms 8044 KB Output is correct
80 Correct 273 ms 8044 KB Output is correct
81 Correct 314 ms 8172 KB Output is correct
82 Correct 294 ms 8044 KB Output is correct
83 Correct 388 ms 8024 KB Output is correct
84 Correct 469 ms 7916 KB Output is correct
85 Correct 382 ms 8024 KB Output is correct
86 Correct 388 ms 8172 KB Output is correct
87 Correct 380 ms 8044 KB Output is correct
88 Correct 422 ms 7916 KB Output is correct
89 Correct 549 ms 7916 KB Output is correct
90 Correct 467 ms 8044 KB Output is correct
91 Correct 489 ms 7916 KB Output is correct
92 Correct 442 ms 8172 KB Output is correct