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답안 #338590

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
338590 2020-12-23T13:12:57 Z blue Mecho (IOI09_mecho) C++11
81 / 100
 1000 ms 8812 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()
{
    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, INF) << '\n';
}

Subtask #1
81.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2796 KB Output is correct
2 Correct 2 ms 2796 KB Output is correct
3 Correct 2 ms 2796 KB Output is correct
4 Correct 2 ms 2796 KB Output is correct
5 Correct 2 ms 2796 KB Output is correct
6 Correct 2 ms 2796 KB Output is correct
7 Correct 540 ms 8684 KB Output is correct
8 Correct 2 ms 2796 KB Output is correct
9 Correct 2 ms 2796 KB Output is correct
10 Correct 2 ms 2796 KB Output is correct
11 Correct 2 ms 2796 KB Output is correct
12 Incorrect 3 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 2796 KB Output is correct
16 Correct 2 ms 2796 KB Output is correct
17 Correct 2 ms 2796 KB Output is correct
18 Correct 2 ms 2796 KB Output is correct
19 Correct 3 ms 2796 KB Output is correct
20 Correct 2 ms 2796 KB Output is correct
21 Correct 2 ms 2796 KB Output is correct
22 Correct 2 ms 2796 KB Output is correct
23 Correct 2 ms 2796 KB Output is correct
24 Correct 3 ms 2796 KB Output is correct
25 Correct 3 ms 2924 KB Output is correct
26 Correct 3 ms 2924 KB Output is correct
27 Correct 3 ms 2924 KB Output is correct
28 Correct 3 ms 2924 KB Output is correct
29 Correct 3 ms 2924 KB Output is correct
30 Correct 3 ms 2924 KB Output is correct
31 Correct 3 ms 2924 KB Output is correct
32 Correct 3 ms 2924 KB Output is correct
33 Correct 18 ms 3820 KB Output is correct
34 Correct 19 ms 3820 KB Output is correct
35 Correct 209 ms 3820 KB Output is correct
36 Correct 20 ms 4076 KB Output is correct
37 Correct 20 ms 4076 KB Output is correct
38 Correct 265 ms 4076 KB Output is correct
39 Correct 26 ms 4460 KB Output is correct
40 Correct 29 ms 4460 KB Output is correct
41 Correct 285 ms 4588 KB Output is correct
42 Correct 28 ms 4844 KB Output is correct
43 Correct 44 ms 4844 KB Output is correct
44 Correct 411 ms 5100 KB Output is correct
45 Correct 36 ms 5228 KB Output is correct
46 Correct 39 ms 5228 KB Output is correct
47 Correct 446 ms 5484 KB Output is correct
48 Correct 46 ms 5612 KB Output is correct
49 Correct 66 ms 5612 KB Output is correct
50 Correct 534 ms 5740 KB Output is correct
51 Correct 51 ms 6124 KB Output is correct
52 Correct 50 ms 6124 KB Output is correct
53 Correct 619 ms 6124 KB Output is correct
54 Correct 65 ms 6764 KB Output is correct
55 Correct 75 ms 6636 KB Output is correct
56 Correct 735 ms 6892 KB Output is correct
57 Correct 62 ms 7788 KB Output is correct
58 Correct 78 ms 7788 KB Output is correct
59 Correct 835 ms 7932 KB Output is correct
60 Correct 73 ms 8428 KB Output is correct
61 Correct 70 ms 8428 KB Output is correct
62 Execution timed out 1079 ms 8684 KB Time limit exceeded
63 Correct 326 ms 8428 KB Output is correct
64 Correct 789 ms 8556 KB Output is correct
65 Correct 546 ms 8564 KB Output is correct
66 Correct 395 ms 8556 KB Output is correct
67 Correct 366 ms 8428 KB Output is correct
68 Correct 197 ms 8428 KB Output is correct
69 Correct 162 ms 8428 KB Output is correct
70 Correct 127 ms 8556 KB Output is correct
71 Correct 126 ms 8428 KB Output is correct
72 Incorrect 93 ms 8428 KB Output isn't correct
73 Incorrect 190 ms 8556 KB Output isn't correct
74 Correct 368 ms 8736 KB Output is correct
75 Correct 318 ms 8684 KB Output is correct
76 Correct 316 ms 8684 KB Output is correct
77 Correct 334 ms 8660 KB Output is correct
78 Correct 413 ms 8684 KB Output is correct
79 Correct 378 ms 8556 KB Output is correct
80 Correct 298 ms 8556 KB Output is correct
81 Correct 353 ms 8556 KB Output is correct
82 Correct 330 ms 8812 KB Output is correct
83 Correct 413 ms 8668 KB Output is correct
84 Correct 470 ms 8684 KB Output is correct
85 Correct 361 ms 8556 KB Output is correct
86 Correct 410 ms 8812 KB Output is correct
87 Correct 406 ms 8556 KB Output is correct
88 Correct 457 ms 8684 KB Output is correct
89 Correct 604 ms 8556 KB Output is correct
90 Correct 496 ms 8556 KB Output is correct
91 Correct 513 ms 8684 KB Output is correct
92 Correct 459 ms 8684 KB Output is correct