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답안 #338623

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
338623 2020-12-23T14:03:59 Z blue Mecho (IOI09_mecho) C++11
100 / 100
 333 ms 8120 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];

int INF = 15e8;

int binary_search(int a, int b)
{
    int m = (a+b)/2+1;
    if(a == b) m = a;

    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();
        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;

    cout << binary_search(0, grid[mecho]-1) << '\n';
}

Subtask #1
100.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 0 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 158 ms 8048 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 1 ms 364 KB Output is correct
12 Correct 1 ms 364 KB Output is correct
13 Correct 1 ms 364 KB Output is 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 364 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 496 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 364 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 1900 KB Output is correct
36 Correct 9 ms 2284 KB Output is correct
37 Correct 11 ms 2284 KB Output is correct
38 Correct 63 ms 2284 KB Output is correct
39 Correct 11 ms 2796 KB Output is correct
40 Correct 14 ms 2796 KB Output is correct
41 Correct 83 ms 2796 KB Output is correct
42 Correct 14 ms 3436 KB Output is correct
43 Correct 16 ms 3308 KB Output is correct
44 Correct 100 ms 3308 KB Output is correct
45 Correct 16 ms 3948 KB Output is correct
46 Correct 20 ms 3948 KB Output is correct
47 Correct 123 ms 3948 KB Output is correct
48 Correct 20 ms 4588 KB Output is correct
49 Correct 24 ms 4588 KB Output is correct
50 Correct 153 ms 4588 KB Output is correct
51 Correct 23 ms 5356 KB Output is correct
52 Correct 28 ms 5356 KB Output is correct
53 Correct 177 ms 5356 KB Output is correct
54 Correct 27 ms 6124 KB Output is correct
55 Correct 32 ms 6124 KB Output is correct
56 Correct 212 ms 6160 KB Output is correct
57 Correct 30 ms 6892 KB Output is correct
58 Correct 37 ms 7020 KB Output is correct
59 Correct 243 ms 7020 KB Output is correct
60 Correct 36 ms 7916 KB Output is correct
61 Correct 42 ms 7916 KB Output is correct
62 Correct 286 ms 8044 KB Output is correct
63 Correct 139 ms 7788 KB Output is correct
64 Correct 333 ms 7916 KB Output is correct
65 Correct 219 ms 7916 KB Output is correct
66 Correct 179 ms 7916 KB Output is correct
67 Correct 163 ms 7916 KB Output is correct
68 Correct 98 ms 7916 KB Output is correct
69 Correct 93 ms 7916 KB Output is correct
70 Correct 58 ms 7852 KB Output is correct
71 Correct 60 ms 7916 KB Output is correct
72 Correct 51 ms 7916 KB Output is correct
73 Correct 77 ms 8044 KB Output is correct
74 Correct 128 ms 8044 KB Output is correct
75 Correct 106 ms 8044 KB Output is correct
76 Correct 97 ms 8044 KB Output is correct
77 Correct 108 ms 8044 KB Output is correct
78 Correct 130 ms 7916 KB Output is correct
79 Correct 114 ms 7916 KB Output is correct
80 Correct 101 ms 7916 KB Output is correct
81 Correct 111 ms 8044 KB Output is correct
82 Correct 99 ms 7916 KB Output is correct
83 Correct 124 ms 7916 KB Output is correct
84 Correct 149 ms 7916 KB Output is correct
85 Correct 125 ms 8044 KB Output is correct
86 Correct 131 ms 8044 KB Output is correct
87 Correct 130 ms 8120 KB Output is correct
88 Correct 147 ms 8044 KB Output is correct
89 Correct 179 ms 7916 KB Output is correct
90 Correct 154 ms 7916 KB Output is correct
91 Correct 163 ms 7916 KB Output is correct
92 Correct 147 ms 7916 KB Output is correct