Submission #338607

# Submission time Handle Problem Language Result Execution time Memory
338607 2020-12-23T13:25:20 Z blue Mecho (IOI09_mecho) C++11
84 / 100
1000 ms 48796 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 = 2e9;

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();

        vector<int> edge; //check down
        edge.clear();
        if(u % N != 0)
        {
            v = u-1;
            if(dist[v] == INF && dist[u] + 1 < grid[v])
            {
                dist[v] = dist[u] + 1;
                tbv.push(v);
            }
        }
        if(u % N != N-1)
        {
            v = u+1;
            if(dist[v] == INF && dist[u] + 1 < grid[v])
            {
                dist[v] = dist[u] + 1;
                tbv.push(v);
            }
        }
        if(u >= N)
        {
            v = u-N;
            if(dist[v] == INF && dist[u] + 1 < grid[v])
            {
                dist[v] = dist[u] + 1;
                tbv.push(v);
            }
        }
        if(u < N*(N+1))
        {
            v = u+N;
            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, 2e9) << '\n';
}
# Verdict Execution time Memory Grader output
1 Correct 1 ms 492 KB Output is correct
2 Correct 0 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 114 ms 8092 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 Execution timed out 1081 ms 48796 KB Time limit exceeded
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 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 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 492 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 22 ms 1772 KB Output is correct
36 Correct 10 ms 2284 KB Output is correct
37 Correct 9 ms 2284 KB Output is correct
38 Correct 30 ms 2284 KB Output is correct
39 Correct 12 ms 2796 KB Output is correct
40 Correct 12 ms 2796 KB Output is correct
41 Correct 37 ms 2796 KB Output is correct
42 Correct 14 ms 3308 KB Output is correct
43 Correct 16 ms 3308 KB Output is correct
44 Correct 50 ms 3252 KB Output is correct
45 Correct 18 ms 3948 KB Output is correct
46 Correct 20 ms 3948 KB Output is correct
47 Correct 71 ms 3948 KB Output is correct
48 Correct 24 ms 4716 KB Output is correct
49 Correct 21 ms 4588 KB Output is correct
50 Correct 76 ms 4716 KB Output is correct
51 Correct 29 ms 5356 KB Output is correct
52 Correct 24 ms 5356 KB Output is correct
53 Correct 103 ms 5356 KB Output is correct
54 Correct 31 ms 6124 KB Output is correct
55 Correct 28 ms 6124 KB Output is correct
56 Correct 145 ms 6124 KB Output is correct
57 Correct 32 ms 7020 KB Output is correct
58 Correct 32 ms 7020 KB Output is correct
59 Correct 148 ms 7020 KB Output is correct
60 Correct 35 ms 7916 KB Output is correct
61 Correct 35 ms 7916 KB Output is correct
62 Correct 170 ms 7916 KB Output is correct
63 Correct 114 ms 7916 KB Output is correct
64 Correct 240 ms 7916 KB Output is correct
65 Correct 170 ms 7916 KB Output is correct
66 Correct 130 ms 7916 KB Output is correct
67 Correct 121 ms 7916 KB Output is correct
68 Correct 80 ms 7916 KB Output is correct
69 Correct 69 ms 7916 KB Output is correct
70 Correct 60 ms 7916 KB Output is correct
71 Correct 60 ms 7916 KB Output is correct
72 Incorrect 53 ms 7916 KB Output isn't correct
73 Incorrect 64 ms 8044 KB Output isn't correct
74 Correct 80 ms 8044 KB Output is correct
75 Correct 80 ms 8044 KB Output is correct
76 Correct 73 ms 8044 KB Output is correct
77 Correct 80 ms 8044 KB Output is correct
78 Correct 79 ms 7916 KB Output is correct
79 Correct 73 ms 7916 KB Output is correct
80 Correct 70 ms 7916 KB Output is correct
81 Correct 73 ms 7916 KB Output is correct
82 Correct 70 ms 7916 KB Output is correct
83 Correct 86 ms 7916 KB Output is correct
84 Correct 90 ms 7916 KB Output is correct
85 Correct 85 ms 7916 KB Output is correct
86 Correct 83 ms 7916 KB Output is correct
87 Correct 83 ms 7916 KB Output is correct
88 Correct 100 ms 7916 KB Output is correct
89 Correct 103 ms 7916 KB Output is correct
90 Correct 96 ms 7916 KB Output is correct
91 Correct 100 ms 7916 KB Output is correct
92 Correct 103 ms 7916 KB Output is correct