oj.uz

Submission #969193

# Submission time Handle Problem Language Result Execution time Memory
969193 2024-04-24T16:20:01 Z anango Mecho (IOI09_mecho) C++17
100 / 100
 891 ms 26552 KB 
#include <bits/stdc++.h>
#define int long long
using namespace std;
int n,s;
vector<vector<int>> dist;
vector<vector<int>> grid;
pair<int,int> start;
pair<int,int> finish;


int debug=0;
int adebug = 0;
int INF=1000000007;
int gval(pair<int,int> cell) {
    return grid[cell.first][cell.second];
}

bool bounds(pair<int,int> cell) {
    return 0<=cell.first && cell.first<n && 0<=cell.second && cell.second<n;
}

vector<pair<int,int>> getnei(pair<int,int> st) {
    if (!(gval(st)==0)) {
        return {};
    }
    vector<pair<int,int>> V={{st.first-1,st.second},{st.first+1,st.second},{st.first,st.second+1},{st.first,st.second-1}};
    vector<pair<int,int>> ans;
    for (auto nei:V) {
        if (bounds(nei) && ((gval(nei)==0) || gval(nei)==2)) {
            ans.push_back(nei);
        }
    }
    return ans;
}

bool BSTA(int time) {
    //returns whether it can be done after waiting this time
    vector<vector<int>> distance(n,vector<int>(n,INF));
    vector<vector<int>> proc(n,vector<int>(n,0));
    deque<pair<int,int>> visited={start};
    distance[start.first][start.second] = 0;
    if (time>=dist[start.first][start.second]) {
        return 0;
    }
    while (visited.size()) {
        pair<int,int> fi=visited[0];
        visited.pop_front();
        if (proc[fi.first][fi.second]) {
            continue;
        }
        proc[fi.first][fi.second] = 1;
        for (auto j:getnei(fi)) {
            int bdist=time+(distance[fi.first][fi.second]+1)/s; 
            //it's the total number of steps the honey has to walk to reach this cell
            if(debug) cout << fi.first << " " << fi.second << " " << j.first << " " << j.second << " "<<bdist << " " <<dist[fi.first][fi.second] << endl;
            if (bdist>=(dist[j.first][j.second])) {
                continue;   
            }
            distance[j.first][j.second] = min(distance[j.first][j.second],distance[fi.first][fi.second]+1);
            visited.push_back(j);
        }
    }
    if(debug || adebug) cout << "BSTA TRYING METHOD CALCULATION TO FIND THE ANSWER" << " " << time << endl;
    int b=distance[finish.first][finish.second] < 3*n*n;

    if (debug || adebug) cout <<b << " " << distance[finish.first][finish.second] << endl;
    for (int i=0; i<n; i++) {
        for (int j=0; j<n; j++) {
            if(debug) cout << distance[i][j] <<" ";
        }
        if(debug) cout << endl;
    }
    return distance[finish.first][finish.second] < 3*n*n;
    
}


vector<pair<int,int>> adjlistbee(pair<int,int> st) {
    if (!(gval(st)==0 || gval(st)==3)) {
        return {};
    }
    vector<pair<int,int>> V={{st.first-1,st.second},{st.first+1,st.second},{st.first,st.second+1},{st.first,st.second-1}};
    vector<pair<int,int>> ans;
    for (auto nei:V) {
        if (bounds(nei) && gval(nei)==0) {
            ans.push_back(nei);
        }
    }
    return ans;
}

signed main() {
    if (debug || adebug) freopen("input.txt","r",stdin);
    if (debug || adebug) freopen("output.txt","w",stdout);
    cin >> n >> s;
    dist=vector<vector<int>>(n,vector<int>(n,INF));
    grid=vector<vector<int>>(n,vector<int>(n,-1));
    vector<vector<int>> proc(n,vector<int>(n,0));
    vector<pair<int,int>> hives;
    deque<pair<int,int>> visited;
    for (int i=0; i<n; i++) {
        string st;
        cin >> st;
        //if(debug) cout << st << endl;
        for (int j=0; j<n; j++) {
            //if(debug) cout << i <<" " << j << " " << st[j] << endl;
            int ans;
            if (st[j]=='G') {
                ans=0;
            }
            else if (st[j]=='M') {
                ans=0;
                start={i,j};
            }
            else if (st[j]=='D') {
                ans=2;
                finish={i,j};
            }
            else if (st[j]=='T') {
                ans=1;
                
            }
            else {
                //assert(st[j]=='H');
                ans=3;
                hives.push_back({i,j});
                dist[i][j] = 0;
                visited.push_back({i,j});
            }
            grid[i][j] = ans;
            //if(debug) cout << i << " " << j << endl;
        }
    }
    //a cell is available to bees if the cell is 0 or 3, 3 denotes starting hives
    //a cell is available to mecho if the dist condition holds and the cell isn't a tree
    while (visited.size()) {
        pair<int,int> fi=visited[0];
        visited.pop_front();
        if (proc[fi.first][fi.second]) {
            continue;
        }
        proc[fi.first][fi.second] = 1;
        for (auto j:adjlistbee(fi)) {
            dist[j.first][j.second] = min(dist[j.first][j.second],dist[fi.first][fi.second]+1);
            visited.push_back(j);
        }
    }
    if(debug) cout << "DISTS"<< endl;
    for (int i=0; i<n; i++) {
        for (int j=0; j<n; j++) {
            //cout << dist[i][j] <<" ";
        }
        if(debug) cout << endl;
    }
    


    int l=0;
    int r=n*n*1;
    while (l<r) {
        int m=(l+r)/2;
        if (!BSTA(m)) {
            l=l;
            r=m;
        }
        else {
            l=m+1;
            r=r;
        }
    }
    if (l==0 && !BSTA(l)) {
        cout << -1 << endl;
        return 0;
    }
    while (l>0 && !BSTA(l)) {
        l--;
    }
    while (BSTA(l+1)) {
        l++;
    }
    if (l==0 && !BSTA(l)) {
        if(debug) cout << -1 << endl;
        return 0;
    }
    cout << l << endl;

}

Compilation message

mecho.cpp: In function 'int main()':
mecho.cpp:93:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |     if (debug || adebug) freopen("input.txt","r",stdin);
      |                          ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
mecho.cpp:94:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |     if (debug || adebug) freopen("output.txt","w",stdout);
      |                          ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 628 ms 25908 KB Output is correct
8 Correct 1 ms 344 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 1 ms 344 KB Output is correct
12 Correct 1 ms 348 KB Output is correct
13 Correct 1 ms 348 KB Output is correct
14 Correct 2 ms 348 KB Output is correct
15 Correct 0 ms 432 KB Output is correct
16 Correct 1 ms 600 KB Output is correct
17 Correct 0 ms 348 KB Output is correct
18 Correct 0 ms 348 KB Output is correct
19 Correct 1 ms 348 KB Output is correct
20 Correct 1 ms 348 KB Output is correct
21 Correct 1 ms 348 KB Output is correct
22 Correct 1 ms 348 KB Output is correct
23 Correct 1 ms 348 KB Output is correct
24 Correct 1 ms 348 KB Output is correct
25 Correct 1 ms 348 KB Output is correct
26 Correct 1 ms 532 KB Output is correct
27 Correct 1 ms 600 KB Output is correct
28 Correct 1 ms 604 KB Output is correct
29 Correct 1 ms 604 KB Output is correct
30 Correct 1 ms 604 KB Output is correct
31 Correct 1 ms 604 KB Output is correct
32 Correct 1 ms 604 KB Output is correct
33 Correct 23 ms 5404 KB Output is correct
34 Correct 27 ms 5512 KB Output is correct
35 Correct 124 ms 5384 KB Output is correct
36 Correct 30 ms 6932 KB Output is correct
37 Correct 33 ms 6916 KB Output is correct
38 Correct 177 ms 6912 KB Output is correct
39 Correct 38 ms 8604 KB Output is correct
40 Correct 41 ms 8528 KB Output is correct
41 Correct 227 ms 8540 KB Output is correct
42 Correct 46 ms 10508 KB Output is correct
43 Correct 52 ms 10620 KB Output is correct
44 Correct 282 ms 10552 KB Output is correct
45 Correct 59 ms 12640 KB Output is correct
46 Correct 61 ms 12656 KB Output is correct
47 Correct 358 ms 12856 KB Output is correct
48 Correct 71 ms 14980 KB Output is correct
49 Correct 75 ms 14960 KB Output is correct
50 Correct 423 ms 14956 KB Output is correct
51 Correct 81 ms 17540 KB Output is correct
52 Correct 90 ms 17416 KB Output is correct
53 Correct 502 ms 17524 KB Output is correct
54 Correct 93 ms 20208 KB Output is correct
55 Correct 103 ms 20296 KB Output is correct
56 Correct 621 ms 20284 KB Output is correct
57 Correct 109 ms 23148 KB Output is correct
58 Correct 127 ms 23144 KB Output is correct
59 Correct 698 ms 23044 KB Output is correct
60 Correct 130 ms 26288 KB Output is correct
61 Correct 136 ms 26156 KB Output is correct
62 Correct 891 ms 26168 KB Output is correct
63 Correct 461 ms 26112 KB Output is correct
64 Correct 641 ms 26208 KB Output is correct
65 Correct 640 ms 26496 KB Output is correct
66 Correct 495 ms 26144 KB Output is correct
67 Correct 436 ms 26204 KB Output is correct
68 Correct 249 ms 26300 KB Output is correct
69 Correct 197 ms 26192 KB Output is correct
70 Correct 184 ms 26172 KB Output is correct
71 Correct 184 ms 26276 KB Output is correct
72 Correct 143 ms 26272 KB Output is correct
73 Correct 227 ms 26288 KB Output is correct
74 Correct 376 ms 26380 KB Output is correct
75 Correct 421 ms 26328 KB Output is correct
76 Correct 405 ms 26552 KB Output is correct
77 Correct 432 ms 26320 KB Output is correct
78 Correct 537 ms 26488 KB Output is correct
79 Correct 332 ms 26300 KB Output is correct
80 Correct 372 ms 26220 KB Output is correct
81 Correct 476 ms 26184 KB Output is correct
82 Correct 383 ms 26224 KB Output is correct
83 Correct 548 ms 26420 KB Output is correct
84 Correct 487 ms 26284 KB Output is correct
85 Correct 453 ms 26272 KB Output is correct
86 Correct 483 ms 26412 KB Output is correct
87 Correct 508 ms 26292 KB Output is correct
88 Correct 582 ms 26320 KB Output is correct
89 Correct 543 ms 26232 KB Output is correct
90 Correct 584 ms 26260 KB Output is correct
91 Correct 588 ms 26276 KB Output is correct
92 Correct 544 ms 26472 KB Output is correct