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답안 #338595

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
338595 2020-12-23T13:16:51 Z blue Mecho (IOI09_mecho) C++11
81 / 100
 1000 ms 8684 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, 2e9) << '\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 3 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 531 ms 8044 KB Output is correct
8 Correct 3 ms 2796 KB Output is correct
9 Correct 2 ms 2796 KB Output is correct
10 Correct 3 ms 2796 KB Output is correct
11 Correct 3 ms 2796 KB Output is correct
12 Incorrect 2 ms 2924 KB Output isn't correct
13 Incorrect 3 ms 2796 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 2 ms 2796 KB Output is correct
20 Correct 3 ms 2796 KB Output is correct
21 Correct 3 ms 2796 KB Output is correct
22 Correct 4 ms 2796 KB Output is correct
23 Correct 3 ms 2924 KB Output is correct
24 Correct 3 ms 2924 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 2892 KB Output is correct
32 Correct 3 ms 2924 KB Output is correct
33 Correct 18 ms 3820 KB Output is correct
34 Correct 18 ms 3820 KB Output is correct
35 Correct 167 ms 3820 KB Output is correct
36 Correct 25 ms 4076 KB Output is correct
37 Correct 20 ms 4204 KB Output is correct
38 Correct 236 ms 4588 KB Output is correct
39 Correct 27 ms 4376 KB Output is correct
40 Correct 30 ms 4588 KB Output is correct
41 Correct 297 ms 4716 KB Output is correct
42 Correct 29 ms 5100 KB Output is correct
43 Correct 44 ms 5104 KB Output is correct
44 Correct 407 ms 5228 KB Output is correct
45 Correct 42 ms 5276 KB Output is correct
46 Correct 41 ms 5560 KB Output is correct
47 Correct 521 ms 5272 KB Output is correct
48 Correct 46 ms 5996 KB Output is correct
49 Correct 59 ms 5868 KB Output is correct
50 Correct 571 ms 5716 KB Output is correct
51 Correct 53 ms 6508 KB Output is correct
52 Correct 54 ms 6508 KB Output is correct
53 Correct 668 ms 6212 KB Output is correct
54 Correct 68 ms 7200 KB Output is correct
55 Correct 66 ms 7204 KB Output is correct
56 Correct 794 ms 7012 KB Output is correct
57 Correct 66 ms 7800 KB Output is correct
58 Correct 84 ms 7704 KB Output is correct
59 Correct 876 ms 7912 KB Output is correct
60 Correct 77 ms 8300 KB Output is correct
61 Correct 74 ms 8416 KB Output is correct
62 Execution timed out 1068 ms 8368 KB Time limit exceeded
63 Correct 336 ms 8420 KB Output is correct
64 Correct 804 ms 8424 KB Output is correct
65 Correct 560 ms 8428 KB Output is correct
66 Correct 438 ms 8300 KB Output is correct
67 Correct 416 ms 8428 KB Output is correct
68 Correct 211 ms 8300 KB Output is correct
69 Correct 160 ms 8300 KB Output is correct
70 Correct 123 ms 8428 KB Output is correct
71 Correct 130 ms 8300 KB Output is correct
72 Incorrect 95 ms 8300 KB Output isn't correct
73 Incorrect 187 ms 8556 KB Output isn't correct
74 Correct 431 ms 8612 KB Output is correct
75 Correct 331 ms 8556 KB Output is correct
76 Correct 298 ms 8676 KB Output is correct
77 Correct 357 ms 8556 KB Output is correct
78 Correct 403 ms 8556 KB Output is correct
79 Correct 362 ms 8684 KB Output is correct
80 Correct 307 ms 8428 KB Output is correct
81 Correct 341 ms 8556 KB Output is correct
82 Correct 319 ms 8532 KB Output is correct
83 Correct 420 ms 8556 KB Output is correct
84 Correct 495 ms 8536 KB Output is correct
85 Correct 370 ms 8556 KB Output is correct
86 Correct 415 ms 8684 KB Output is correct
87 Correct 403 ms 8556 KB Output is correct
88 Correct 446 ms 8556 KB Output is correct
89 Correct 641 ms 8556 KB Output is correct
90 Correct 497 ms 8684 KB Output is correct
91 Correct 567 ms 8684 KB Output is correct
92 Correct 484 ms 8556 KB Output is correct