답안 #969193

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
969193	2024-04-24T16:20:01 Z	anango	Mecho (IOI09_mecho)	C++17	100 / 100	891 ms	26552 KB

mecho

#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

#	결과	실행 시간	메모리	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