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답안 #338602

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
338602 2020-12-23T13:21:02 Z blue Mecho (IOI09_mecho) C++11
84 / 100
 1000 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 = 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;
    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()
{
    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;
    }

    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
84.0 / 100.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 0 ms 364 KB Output is correct
3 Correct 1 ms 512 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 471 ms 8044 KB Output is correct
8 Correct 1 ms 492 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 1080 ms 5432 KB Time limit exceeded
13 Incorrect 1 ms 364 KB Output isn't correct
14 Correct 2 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 512 KB Output is correct
18 Correct 1 ms 504 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 492 KB Output is correct
30 Correct 1 ms 492 KB Output is correct
31 Correct 1 ms 512 KB Output is correct
32 Correct 1 ms 492 KB Output is correct
33 Correct 10 ms 1772 KB Output is correct
34 Correct 11 ms 1772 KB Output is correct
35 Correct 160 ms 1772 KB Output is correct
36 Correct 11 ms 2284 KB Output is correct
37 Correct 10 ms 2284 KB Output is correct
38 Correct 218 ms 2284 KB Output is correct
39 Correct 15 ms 2796 KB Output is correct
40 Correct 19 ms 2796 KB Output is correct
41 Correct 334 ms 2796 KB Output is correct
42 Correct 14 ms 3308 KB Output is correct
43 Correct 29 ms 3308 KB Output is correct
44 Correct 356 ms 3308 KB Output is correct
45 Correct 26 ms 3972 KB Output is correct
46 Correct 26 ms 3948 KB Output is correct
47 Correct 435 ms 3948 KB Output is correct
48 Correct 26 ms 4588 KB Output is correct
49 Correct 38 ms 4716 KB Output is correct
50 Correct 523 ms 4644 KB Output is correct
51 Correct 31 ms 5356 KB Output is correct
52 Correct 29 ms 5356 KB Output is correct
53 Correct 620 ms 5484 KB Output is correct
54 Correct 40 ms 6124 KB Output is correct
55 Correct 40 ms 6124 KB Output is correct
56 Correct 724 ms 6420 KB Output is correct
57 Correct 35 ms 7148 KB Output is correct
58 Correct 51 ms 7020 KB Output is correct
59 Correct 946 ms 7020 KB Output is correct
60 Correct 40 ms 7916 KB Output is correct
61 Correct 45 ms 7916 KB Output is correct
62 Correct 980 ms 8044 KB Output is correct
63 Correct 296 ms 7916 KB Output is correct
64 Correct 766 ms 8172 KB Output is correct
65 Correct 516 ms 8044 KB Output is correct
66 Correct 373 ms 8044 KB Output is correct
67 Correct 330 ms 8172 KB Output is correct
68 Correct 168 ms 7916 KB Output is correct
69 Correct 123 ms 7892 KB Output is correct
70 Correct 88 ms 7916 KB Output is correct
71 Correct 93 ms 8044 KB Output is correct
72 Incorrect 61 ms 7916 KB Output isn't correct
73 Incorrect 152 ms 8044 KB Output isn't correct
74 Correct 373 ms 8172 KB Output is correct
75 Correct 284 ms 8172 KB Output is correct
76 Correct 260 ms 8172 KB Output is correct
77 Correct 300 ms 8172 KB Output is correct
78 Correct 428 ms 7916 KB Output is correct
79 Correct 321 ms 8044 KB Output is correct
80 Correct 259 ms 7916 KB Output is correct
81 Correct 301 ms 7916 KB Output is correct
82 Correct 280 ms 7916 KB Output is correct
83 Correct 373 ms 8044 KB Output is correct
84 Correct 452 ms 8044 KB Output is correct
85 Correct 369 ms 8044 KB Output is correct
86 Correct 385 ms 8044 KB Output is correct
87 Correct 379 ms 7916 KB Output is correct
88 Correct 421 ms 7916 KB Output is correct
89 Correct 551 ms 7916 KB Output is correct
90 Correct 469 ms 7916 KB Output is correct
91 Correct 477 ms 8108 KB Output is correct
92 Correct 435 ms 7916 KB Output is correct