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Submission #338609

# Submission time Handle Problem Language Result Execution time Memory
338609 2020-12-23T13:29:13 Z blue Mecho (IOI09_mecho) C++11
84 / 100
 253 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();

        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, 2e8) << '\n';
}

Subtask #1
84.0 / 100.0

# Verdict Execution time Memory 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 99 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 1 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 492 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 384 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 384 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 23 ms 1772 KB Output is correct
36 Correct 9 ms 2284 KB Output is correct
37 Correct 11 ms 2284 KB Output is correct
38 Correct 35 ms 2284 KB Output is correct
39 Correct 11 ms 2796 KB Output is correct
40 Correct 12 ms 2796 KB Output is correct
41 Correct 42 ms 2796 KB Output is correct
42 Correct 14 ms 3308 KB Output is correct
43 Correct 14 ms 3308 KB Output is correct
44 Correct 50 ms 3308 KB Output is correct
45 Correct 16 ms 3948 KB Output is correct
46 Correct 17 ms 3948 KB Output is correct
47 Correct 61 ms 3948 KB Output is correct
48 Correct 20 ms 4716 KB Output is correct
49 Correct 19 ms 4588 KB Output is correct
50 Correct 107 ms 4588 KB Output is correct
51 Correct 23 ms 5356 KB Output is correct
52 Correct 24 ms 5356 KB Output is correct
53 Correct 100 ms 5484 KB Output is correct
54 Correct 26 ms 6124 KB Output is correct
55 Correct 30 ms 6124 KB Output is correct
56 Correct 116 ms 6124 KB Output is correct
57 Correct 31 ms 7020 KB Output is correct
58 Correct 38 ms 7020 KB Output is correct
59 Correct 144 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 182 ms 7916 KB Output is correct
63 Correct 115 ms 7916 KB Output is correct
64 Correct 253 ms 8044 KB Output is correct
65 Correct 155 ms 7916 KB Output is correct
66 Correct 139 ms 7916 KB Output is correct
67 Correct 125 ms 8044 KB Output is correct
68 Correct 84 ms 7804 KB Output is correct
69 Correct 88 ms 7916 KB Output is correct
70 Correct 64 ms 7900 KB Output is correct
71 Correct 65 ms 7916 KB Output is correct
72 Incorrect 54 ms 7916 KB Output isn't correct
73 Incorrect 59 ms 8044 KB Output isn't correct
74 Correct 75 ms 8044 KB Output is correct
75 Correct 74 ms 8044 KB Output is correct
76 Correct 71 ms 8172 KB Output is correct
77 Correct 77 ms 8044 KB Output is correct
78 Correct 90 ms 8044 KB Output is correct
79 Correct 78 ms 7916 KB Output is correct
80 Correct 88 ms 7916 KB Output is correct
81 Correct 71 ms 7916 KB Output is correct
82 Correct 72 ms 8044 KB Output is correct
83 Correct 85 ms 7916 KB Output is correct
84 Correct 88 ms 7916 KB Output is correct
85 Correct 79 ms 7916 KB Output is correct
86 Correct 90 ms 7916 KB Output is correct
87 Correct 103 ms 7916 KB Output is correct
88 Correct 118 ms 7916 KB Output is correct
89 Correct 108 ms 7916 KB Output is correct
90 Correct 109 ms 7916 KB Output is correct
91 Correct 101 ms 8044 KB Output is correct
92 Correct 93 ms 7916 KB Output is correct