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답안 #338593

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
338593 2020-12-23T13:15:48 Z blue Mecho (IOI09_mecho) C++11
60 / 100
 1000 ms 8044 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, 1e6) << '\n';
}

Subtask #1
60.0 / 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 496 ms 8044 KB Output is correct
8 Correct 2 ms 2828 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 2 ms 2796 KB Output isn't correct
13 Incorrect 3 ms 2796 KB Output isn't correct
14 Correct 3 ms 2796 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 2 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 3 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 2 ms 2796 KB Output is correct
26 Correct 3 ms 2796 KB Output is correct
27 Correct 2 ms 2924 KB Output is correct
28 Correct 2 ms 2924 KB Output is correct
29 Correct 3 ms 2924 KB Output is correct
30 Correct 3 ms 2944 KB Output is correct
31 Correct 3 ms 2924 KB Output is correct
32 Correct 3 ms 2924 KB Output is correct
33 Correct 17 ms 3820 KB Output is correct
34 Incorrect 113 ms 3820 KB Output isn't correct
35 Correct 157 ms 3964 KB Output is correct
36 Correct 18 ms 4076 KB Output is correct
37 Incorrect 191 ms 4204 KB Output isn't correct
38 Correct 233 ms 4076 KB Output is correct
39 Correct 25 ms 4460 KB Output is correct
40 Incorrect 207 ms 4460 KB Output isn't correct
41 Correct 283 ms 4592 KB Output is correct
42 Correct 32 ms 4844 KB Output is correct
43 Incorrect 261 ms 4976 KB Output isn't correct
44 Correct 362 ms 4972 KB Output is correct
45 Correct 33 ms 5228 KB Output is correct
46 Incorrect 320 ms 5484 KB Output isn't correct
47 Correct 445 ms 5356 KB Output is correct
48 Correct 43 ms 5612 KB Output is correct
49 Incorrect 381 ms 5740 KB Output isn't correct
50 Correct 535 ms 5840 KB Output is correct
51 Correct 49 ms 6124 KB Output is correct
52 Incorrect 457 ms 6260 KB Output isn't correct
53 Correct 659 ms 6252 KB Output is correct
54 Correct 62 ms 6844 KB Output is correct
55 Incorrect 541 ms 6764 KB Output isn't correct
56 Correct 735 ms 6892 KB Output is correct
57 Correct 58 ms 7276 KB Output is correct
58 Incorrect 678 ms 7532 KB Output isn't correct
59 Correct 870 ms 7532 KB Output is correct
60 Correct 66 ms 7788 KB Output is correct
61 Incorrect 693 ms 7916 KB Output isn't correct
62 Execution timed out 1002 ms 8044 KB Time limit exceeded
63 Correct 324 ms 7788 KB Output is correct
64 Correct 772 ms 7916 KB Output is correct
65 Correct 490 ms 7916 KB Output is correct
66 Correct 416 ms 7788 KB Output is correct
67 Correct 357 ms 7916 KB Output is correct
68 Correct 196 ms 7788 KB Output is correct
69 Correct 186 ms 7788 KB Output is correct
70 Correct 114 ms 7788 KB Output is correct
71 Correct 104 ms 7916 KB Output is correct
72 Incorrect 89 ms 7788 KB Output isn't correct
73 Incorrect 179 ms 7916 KB Output isn't correct
74 Correct 349 ms 8044 KB Output is correct
75 Correct 312 ms 7916 KB Output is correct
76 Correct 281 ms 7916 KB Output is correct
77 Correct 319 ms 8044 KB Output is correct
78 Correct 393 ms 7916 KB Output is correct
79 Correct 347 ms 7916 KB Output is correct
80 Correct 291 ms 7916 KB Output is correct
81 Correct 334 ms 8020 KB Output is correct
82 Correct 304 ms 7916 KB Output is correct
83 Correct 399 ms 8044 KB Output is correct
84 Correct 465 ms 7916 KB Output is correct
85 Correct 394 ms 7916 KB Output is correct
86 Correct 397 ms 8044 KB Output is correct
87 Correct 424 ms 8044 KB Output is correct
88 Correct 450 ms 7916 KB Output is correct
89 Correct 573 ms 8044 KB Output is correct
90 Correct 482 ms 8044 KB Output is correct
91 Correct 510 ms 7916 KB Output is correct
92 Correct 458 ms 7916 KB Output is correct