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Submission #393890

# Submission time Handle Problem Language Result Execution time Memory
393890 2021-04-24T19:02:15 Z MaisyDoge13 Mecho (IOI09_mecho) C++17
100 / 100
 288 ms 16360 KB 
#include <iostream>
#include <cstdio>
#include <vector>
#include <utility>
#include <cmath>
#include <algorithm>
#include <array>
#include <set>
#include <climits>
#include <map>
#include <memory>
#include <string>
#include <deque>
using namespace std;

#define input "mecho.in"
#define output "mecho.out"
#define int long long
int n, s;
int ans=-1; //will be maxed during the binary search
vector<vector<int>> bees_reach;
deque<pair<int, int>> bees_bfs; //r, c start off while taking input
vector<string> a;//input field
vector<vector<int>> reach_copy;
deque<pair<int, int>> bfs_copy;
vector<pair<int, int>> dirs = {
    {1, 0},
    {-1, 0},
    {0, 1},
    {0, -1}
};
bool check(int m) {
    vector<vector<int>> mecho_reach = reach_copy;
    deque<pair<int, int>> mecho_bfs = bfs_copy;
    if (bees_reach[mecho_bfs.front().first][mecho_bfs.front().second]<=(m*s)) return 0;
    //do bfs with mecho's location except mech can never go to a tile with bees there less than or equal to (m*s)+steps
    while (!mecho_bfs.empty()) {
        pair<int, int> curr=mecho_bfs.front();
        mecho_bfs.pop_front();
        int r=curr.first, c=curr.second;
        int curr_steps=mecho_reach[r][c];
        //cout << "r " << r << " c " << c << " curr_steps " <<  curr_steps << endl;
        if (a[r][c]=='D') {
            return 1;
        }
        for (pair<int, int> dir: dirs) {
            int new_r=r+dir.first, new_c=c+dir.second;
            if (new_r<0 || new_r>=n || new_c<0 || new_c>=n || a[new_r][new_c]=='T' || mecho_reach[new_r][new_c]!=-1) continue;
            if (bees_reach[new_r][new_c]<=(m*s)+curr_steps+1 && bees_reach[new_r][new_c]!=-1) continue;
            mecho_reach[new_r][new_c]=curr_steps+1;
            mecho_bfs.push_back({new_r, new_c});
        }
    }


    return 0;
}
signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    //freopen(input, "r", stdin);
    //freopen(output, "w", stdout);
    cin >> n >> s;
    bees_reach.resize(n, vector<int>(n, -1));
    reach_copy.resize(n, vector<int>(n, -1));
    a.reserve(n);
    for (int r=0;r<n;r++) {
        string s; cin >> s;
        a.push_back(s);
        for (int c=0;c<n;c++) {
            if (a[r][c]=='H') {
                bees_bfs.push_back({r, c});
                bees_reach[r][c]=0;
            }
            else if (a[r][c]=='M') {
                bfs_copy.push_back({r, c});
                reach_copy[r][c]=0;
            }
        }   
    }
    while (!bees_bfs.empty()) {
        pair<int, int> curr=bees_bfs.front();
        bees_bfs.pop_front();
        int r=curr.first, c=curr.second; int curr_steps=bees_reach[r][c];
        for (pair<int, int> dir: dirs) {
            int new_r=r+dir.first, new_c=c+dir.second;
            if (new_r<0 || new_r>=n || new_c<0 || new_c>=n || a[new_r][new_c]=='T' || a[new_r][new_c]=='D') continue;
            if (bees_reach[new_r][new_c]==-1) {
                bees_reach[new_r][new_c]=curr_steps+s;
                bees_bfs.push_back({new_r, new_c});
            }
        }
    }
    int l=0, r=1000*1000;
    while (l<=r) {
        int m=(l+r)/2;
        //cout << m << endl;
        if (check(m)) {
            ans=m;
            l=m+1;
        }
        else {
            r=m-1;
        }
    }
    cout << ans << endl;
}

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 208 KB Output is correct
2 Correct 1 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 1 ms 204 KB Output is correct
5 Correct 1 ms 204 KB Output is correct
6 Correct 1 ms 204 KB Output is correct
7 Correct 169 ms 16340 KB Output is correct
8 Correct 1 ms 204 KB Output is correct
9 Correct 1 ms 204 KB Output is correct
10 Correct 1 ms 204 KB Output is correct
11 Correct 1 ms 204 KB Output is correct
12 Correct 1 ms 332 KB Output is correct
13 Correct 1 ms 332 KB Output is correct
14 Correct 1 ms 332 KB Output is correct
15 Correct 1 ms 332 KB Output is correct
16 Correct 2 ms 332 KB Output is correct
17 Correct 1 ms 332 KB Output is correct
18 Correct 1 ms 332 KB Output is correct
19 Correct 1 ms 332 KB Output is correct
20 Correct 1 ms 332 KB Output is correct
21 Correct 1 ms 332 KB Output is correct
22 Correct 1 ms 332 KB Output is correct
23 Correct 1 ms 332 KB Output is correct
24 Correct 1 ms 332 KB Output is correct
25 Correct 1 ms 332 KB Output is correct
26 Correct 1 ms 332 KB Output is correct
27 Correct 1 ms 332 KB Output is correct
28 Correct 1 ms 332 KB Output is correct
29 Correct 1 ms 332 KB Output is correct
30 Correct 1 ms 332 KB Output is correct
31 Correct 1 ms 460 KB Output is correct
32 Correct 1 ms 460 KB Output is correct
33 Correct 10 ms 3368 KB Output is correct
34 Correct 7 ms 3384 KB Output is correct
35 Correct 30 ms 3380 KB Output is correct
36 Correct 7 ms 4300 KB Output is correct
37 Correct 7 ms 4300 KB Output is correct
38 Correct 40 ms 4364 KB Output is correct
39 Correct 20 ms 5360 KB Output is correct
40 Correct 10 ms 5324 KB Output is correct
41 Correct 59 ms 5388 KB Output is correct
42 Correct 21 ms 6596 KB Output is correct
43 Correct 13 ms 6524 KB Output is correct
44 Correct 64 ms 6636 KB Output is correct
45 Correct 25 ms 7872 KB Output is correct
46 Correct 14 ms 7844 KB Output is correct
47 Correct 94 ms 7888 KB Output is correct
48 Correct 33 ms 9308 KB Output is correct
49 Correct 18 ms 9248 KB Output is correct
50 Correct 106 ms 9288 KB Output is correct
51 Correct 37 ms 10776 KB Output is correct
52 Correct 23 ms 10804 KB Output is correct
53 Correct 119 ms 10820 KB Output is correct
54 Correct 47 ms 12492 KB Output is correct
55 Correct 27 ms 12452 KB Output is correct
56 Correct 159 ms 12620 KB Output is correct
57 Correct 53 ms 14404 KB Output is correct
58 Correct 31 ms 14232 KB Output is correct
59 Correct 174 ms 14296 KB Output is correct
60 Correct 35 ms 16084 KB Output is correct
61 Correct 35 ms 16076 KB Output is correct
62 Correct 209 ms 16200 KB Output is correct
63 Correct 194 ms 16172 KB Output is correct
64 Correct 288 ms 16136 KB Output is correct
65 Correct 245 ms 16288 KB Output is correct
66 Correct 198 ms 16184 KB Output is correct
67 Correct 179 ms 16176 KB Output is correct
68 Correct 105 ms 16256 KB Output is correct
69 Correct 110 ms 16240 KB Output is correct
70 Correct 98 ms 16260 KB Output is correct
71 Correct 88 ms 16244 KB Output is correct
72 Correct 80 ms 16220 KB Output is correct
73 Correct 95 ms 16312 KB Output is correct
74 Correct 125 ms 16360 KB Output is correct
75 Correct 127 ms 16264 KB Output is correct
76 Correct 119 ms 16228 KB Output is correct
77 Correct 127 ms 16256 KB Output is correct
78 Correct 133 ms 16268 KB Output is correct
79 Correct 109 ms 16232 KB Output is correct
80 Correct 116 ms 16212 KB Output is correct
81 Correct 133 ms 16248 KB Output is correct
82 Correct 107 ms 16336 KB Output is correct
83 Correct 152 ms 16216 KB Output is correct
84 Correct 143 ms 16228 KB Output is correct
85 Correct 135 ms 16220 KB Output is correct
86 Correct 146 ms 16236 KB Output is correct
87 Correct 145 ms 16252 KB Output is correct
88 Correct 153 ms 16208 KB Output is correct
89 Correct 156 ms 16240 KB Output is correct
90 Correct 168 ms 16236 KB Output is correct
91 Correct 152 ms 16220 KB Output is correct
92 Correct 159 ms 16264 KB Output is correct