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답안 #338610

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
338610 2020-12-23T13:31:49 Z blue Mecho (IOI09_mecho) C++11
84 / 100
 347 ms 8172 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;
int dist[800*800];
//LOOKS GOOD

int INF = 15e8;

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, v;
    while(!tbv.empty())
    {
        u = tbv.front();
    //    cout << u << ' ' << dist[u] << '\n';
        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(dist[v] == INF && dist[u] + 1 < grid[v])
            {
                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;
    }

    int visit[N*N];
    for(int i = 0; i < N*N; i++) visit[i] = 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, 2e8) << '\n';
}

Compilation message

mecho.cpp: In function 'int binary_search(int, int)':
mecho.cpp:44:12: warning: unused variable 'v' [-Wunused-variable]
   44 |     int u, v;
      |            ^

Subtask #1
84.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 1 ms 364 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 151 ms 7916 KB Output is correct
8 Correct 1 ms 364 KB Output is correct
9 Correct 1 ms 364 KB Output is correct
10 Correct 1 ms 364 KB Output is correct
11 Correct 0 ms 364 KB Output is correct
12 Incorrect 1 ms 364 KB Output isn't correct
13 Incorrect 1 ms 364 KB Output isn't correct
14 Correct 1 ms 364 KB Output is correct
15 Correct 1 ms 364 KB Output is correct
16 Correct 1 ms 364 KB Output is correct
17 Correct 1 ms 364 KB Output is correct
18 Correct 1 ms 384 KB Output is correct
19 Correct 1 ms 364 KB Output is correct
20 Correct 1 ms 364 KB Output is correct
21 Correct 1 ms 364 KB Output is correct
22 Correct 1 ms 364 KB Output is correct
23 Correct 1 ms 364 KB Output is correct
24 Correct 1 ms 364 KB Output is correct
25 Correct 1 ms 364 KB Output is correct
26 Correct 1 ms 364 KB Output is correct
27 Correct 1 ms 364 KB Output is correct
28 Correct 1 ms 364 KB Output is correct
29 Correct 1 ms 364 KB Output is correct
30 Correct 1 ms 364 KB Output is correct
31 Correct 1 ms 364 KB Output is correct
32 Correct 1 ms 492 KB Output is correct
33 Correct 7 ms 1772 KB Output is correct
34 Correct 8 ms 1772 KB Output is correct
35 Correct 46 ms 1792 KB Output is correct
36 Correct 9 ms 2284 KB Output is correct
37 Correct 10 ms 2284 KB Output is correct
38 Correct 67 ms 2412 KB Output is correct
39 Correct 11 ms 2796 KB Output is correct
40 Correct 13 ms 2796 KB Output is correct
41 Correct 92 ms 2796 KB Output is correct
42 Correct 14 ms 3308 KB Output is correct
43 Correct 15 ms 3308 KB Output is correct
44 Correct 107 ms 3308 KB Output is correct
45 Correct 18 ms 3948 KB Output is correct
46 Correct 19 ms 3948 KB Output is correct
47 Correct 135 ms 3948 KB Output is correct
48 Correct 21 ms 4588 KB Output is correct
49 Correct 22 ms 4588 KB Output is correct
50 Correct 167 ms 4588 KB Output is correct
51 Correct 24 ms 5356 KB Output is correct
52 Correct 25 ms 5356 KB Output is correct
53 Correct 184 ms 5484 KB Output is correct
54 Correct 27 ms 6124 KB Output is correct
55 Correct 30 ms 6252 KB Output is correct
56 Correct 222 ms 6124 KB Output is correct
57 Correct 32 ms 7020 KB Output is correct
58 Correct 31 ms 7020 KB Output is correct
59 Correct 253 ms 7148 KB Output is correct
60 Correct 36 ms 7916 KB Output is correct
61 Correct 36 ms 7908 KB Output is correct
62 Correct 297 ms 8044 KB Output is correct
63 Correct 150 ms 8044 KB Output is correct
64 Correct 347 ms 7916 KB Output is correct
65 Correct 215 ms 8172 KB Output is correct
66 Correct 189 ms 7924 KB Output is correct
67 Correct 174 ms 7916 KB Output is correct
68 Correct 102 ms 7916 KB Output is correct
69 Correct 85 ms 8112 KB Output is correct
70 Correct 74 ms 7916 KB Output is correct
71 Correct 70 ms 7916 KB Output is correct
72 Incorrect 58 ms 7916 KB Output isn't correct
73 Incorrect 74 ms 8044 KB Output isn't correct
74 Correct 119 ms 8044 KB Output is correct
75 Correct 111 ms 8044 KB Output is correct
76 Correct 109 ms 8044 KB Output is correct
77 Correct 115 ms 8044 KB Output is correct
78 Correct 132 ms 7916 KB Output is correct
79 Correct 134 ms 7916 KB Output is correct
80 Correct 107 ms 7916 KB Output is correct
81 Correct 115 ms 7916 KB Output is correct
82 Correct 105 ms 8044 KB Output is correct
83 Correct 130 ms 7916 KB Output is correct
84 Correct 149 ms 7916 KB Output is correct
85 Correct 128 ms 7916 KB Output is correct
86 Correct 141 ms 7916 KB Output is correct
87 Correct 139 ms 7916 KB Output is correct
88 Correct 148 ms 7916 KB Output is correct
89 Correct 177 ms 8172 KB Output is correct
90 Correct 160 ms 8044 KB Output is correct
91 Correct 165 ms 8044 KB Output is correct
92 Correct 153 ms 8044 KB Output is correct