CSES - BOI 2026 Mirror Day 1

Submission details
Task:	Island
Sender:	Mauricio_Cruz
Submission time:	2026-04-16 15:02:42 +0300
Language:	C++ (C++17)
Status:	READY
Result:	10

Feedback
subtask	verdict	score
#1	ACCEPTED	10
#2	WRONG ANSWER	0
#3	WRONG ANSWER	0
#4	WRONG ANSWER	0
#5	WRONG ANSWER	0

Test results
test	verdict	time	subtask
#1	ACCEPTED	0.02 s	1, 5	details
#2	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#3	ACCEPTED	0.15 s	1, 5	details
#4	ACCEPTED	0.15 s	1, 5	details
#5	ACCEPTED	0.13 s	1, 3, 5	details
#6	ACCEPTED	0.08 s	1, 2, 4, 5	details
#7	ACCEPTED	0.08 s	1, 2, 4, 5	details
#8	ACCEPTED	0.17 s	1, 5	details
#9	ACCEPTED	0.16 s	1, 5	details
#10	ACCEPTED	0.07 s	1, 3, 4, 5	details
#11	ACCEPTED	0.07 s	1, 3, 5	details
#12	ACCEPTED	0.12 s	1, 4, 5	details
#13	ACCEPTED	0.11 s	1, 3, 4, 5	details
#14	ACCEPTED	0.11 s	1, 4, 5	details
#15	ACCEPTED	0.10 s	1, 5	details
#16	ACCEPTED	0.13 s	1, 5	details
#17	ACCEPTED	0.14 s	1, 5	details
#18	ACCEPTED	0.17 s	1, 5	details
#19	WRONG ANSWER	0.10 s	2, 4, 5	details
#20	WRONG ANSWER	0.10 s	2, 4, 5	details
#21	WRONG ANSWER	0.09 s	2, 4, 5	details
#22	WRONG ANSWER	0.12 s	2, 4, 5	details
#23	WRONG ANSWER	0.12 s	3, 5	details
#24	WRONG ANSWER	0.12 s	3, 5	details
#25	WRONG ANSWER	0.12 s	3, 5	details
#26	ACCEPTED	0.10 s	3, 5	details
#27	ACCEPTED	0.10 s	3, 4, 5	details
#28	ACCEPTED	0.09 s	3, 4, 5	details
#29	WRONG ANSWER	0.09 s	4, 5	details
#30	WRONG ANSWER	0.10 s	4, 5	details
#31	WRONG ANSWER	0.13 s	4, 5	details
#32	WRONG ANSWER	0.11 s	4, 5	details
#33	WRONG ANSWER	0.11 s	4, 5	details
#34	WRONG ANSWER	0.09 s	4, 5	details
#35	WRONG ANSWER	0.13 s	5	details
#36	WRONG ANSWER	0.12 s	5	details
#37	WRONG ANSWER	0.12 s	5	details
#38	WRONG ANSWER	0.12 s	5	details
#39	WRONG ANSWER	0.12 s	5	details
#40	WRONG ANSWER	0.12 s	5	details
#41	WRONG ANSWER	0.11 s	5	details
#42	WRONG ANSWER	0.11 s	5	details
#43	WRONG ANSWER	0.12 s	5	details
#44	WRONG ANSWER	0.12 s	5	details

Code

#include <bits/stdc++.h>
using namespace std;

#define rz(a,n) a.resize(n); 
#define mset multiset
#define mii map<int,int>
#define str string
#define dbl double
#define i128 __int128
#define to_string tos

#define all(x) x.begin(), x.end()

#define srtl(x)sort(all(x))
#define srtg(x)sort((x).begin(),(x).end(),greater<>())
#define rev(x) reverse(all(x))
#define lb(x,y) lower_bound(x.begin(),x.end(),y)-x.begin()
#define ub(x,y) upper_bound(x.begin(),x.end(),y)-x.begin()

#define ios ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);

#define f first
#define s second
#define pb push_back
#define ins insert
#define next next_permutation(all())
#define _b __builtin_popcount

#define ve vector
#define pii pair<int,int>
#define piii pair<int,pii>
#define vi vector<int>
#define vii vector<pii>
#define viii vector<piii>
#define vvi vector<vi>
#define vst vector<string>
#define vb vector<bool>

#define pV(x)for(auto i:x)cout<<i<<" ";

#define geta(a){for(auto &i:a)cin>>i;}
#define getaa(a){for(int i=1;i<a.size();i++)cin>>a[i];}

#define fri(n)for(int i=0;i<n;i++)
#define frj(j,m)for(int j=0;j<m;j++)
#define ff(v,x,y)for(int v=x;v<y;v++)
#define Fr(n)for(int i=n-1;i>=0;i--)

#define suma(a)accumulate(a.begin(),a.end(),0LL)

#define br(x){cout<<x<<"\n";return;}
#define yesn cout<<"YES\n";

#define yes()br("YES");
#define no(){br("NO")}

#define alice() br("Alice");
#define bob() br("Bob");

#define cn continue;

#define cint const int
#define int long long


int mod=1000000007;
cint mod1=100000007;
cint mod2=998244353;

int ax[8]={0,1,0,-1,-1,1,1,-1};
int ay[8]={1,0,-1,0,1,-1,1,-1};

//bool on(int x,int y){return (x>=0&&x<n&&y>=0&&y<m);}
//int euc(int a,int b,int c,int d){return abs(a-c)+abs(b-d);}

int bp(int x,int y){
	if(y==0)return 1;
	int r=bp(x,y/2);
	return (y&1)?r*r%mod*x%mod:r*r%mod;
}
int bpm(int x,int y){
	if(y==0)return 1;
	int r=bpm(x,y/2);
	return (y&1)?r*r*x:r*r;
}

int cinn(){
	int n;
	cin>>n;
	return n;
}
#define w cinn()
int n,q;

ve<ve<char>>mt(1005,ve<char>(1005,'.'));
int id=0;
vvi dis(1005,vi(1005,0));
vvi vis(1005,vi(1005,0));

int dfs(int x1,int y1,int x2,int y2){
	if(x1==x2&&y1==y2)return 0;
    id++;
    queue<pii>q1;
    q1.push({x1,y1});
    vis[x1][y1]=id;
    dis[x1][y1]=0;

    while(!q1.empty()) {
        pii p=q1.front();
        q1.pop();

        int x=p.f,y=p.s;
        fri(4){
            int X=x+ax[i],Y=y+ay[i];
            if(X>=0&&X<n&&Y>=0&&Y<n&&mt[X][Y]=='#'&&vis[X][Y]!=id){
                vis[X][Y]=id;
                dis[X][Y]=dis[x][y]+1;
                if(X==x2&&Y==y2)return dis[X][Y];
                q1.push({X,Y});
            }
        }
    }
    return -1;
}

void bfs(int x,int y,int d){
	id++;
    queue<pii>q1;
    q1.push({x,y});
    vis[x][y]=id;
    dis[x][y]=0;
    while(!q1.empty()) {
        pii p=q1.front();
        q1.pop();

        int curx=p.f,cury=p.s;
        fri(4){
            int X=curx+ax[i],Y=cury+ay[i];
            if(X>=0&&X<n&&Y>=0&&Y<n&&mt[X][Y]=='#'&&vis[X][Y]!=id){
                vis[X][Y]=id;
                dis[X][Y]=dis[curx][cury]+1;
                q1.push({X,Y});
            }
        }
    }
}

void solve(){
	cin>>n>>q;
	for(int i=0;i<n;i++)
	for(int j=0;j<n;j++)
	cin>>mt[i][j];

	if(n<=200&&q<=200){
		while(q--){
			int x1,y1,x2,y2;
			cin>>x1>>y1>>x2>>y2;x1--;x2--;y1--;y2--;
			cout<<dfs(x1,y1,x2,y2)<<"\n";
		}
	}
	else{
		int xxx=0,yyy=0;
		bool ff = false;
		for(int ii=0;ii<n;ii++){
    		for(int jj=0;jj<n;jj++){
        		if(mt[ii][jj]=='#'){
        			int num=0;
        			fri(4){
                        int X=ii+ax[i],Y=jj+ay[i];
                        if(X>=0&&X<n&&Y>=0&&Y<n&&mt[X][Y]=='#')num++;
        			}
        			if(num<=1){xxx=ii,yyy=jj; ff=true; break;}
        		}
    		}
    		if(ff) break;
		}
		bfs(xxx,yyy,0);
		while(q--){
			int x1,y1,x2,y2;
			cin>>x1>>y1>>x2>>y2;x1--;x2--;y1--;y2--;
			cout<<abs(dis[x1][y1]-dis[x2][y2])<<"\n";
		}
	}
}

int32_t main(){
	ios;
	int t=1;
	while(t--){
		solve();
	}
	return 0;
}





/*

*/

Test details

Test 1

Subtask: 1, 5

Verdict: ACCEPTED

input
`8 4 ........ ..####.. .##.###. .##.###. ...` view save

correct output
`5 0 17 3` view save

user output
`5 0 17 3` view save

Test 2

Subtask: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`3 1 ... .#. ... 2 2 2 2` view save

correct output
`0` view save

user output
`0` view save

Test 3

Subtask: 1, 5

Verdict: ACCEPTED

input
`199 196 .................................` view save

correct output
`468 605 825 532 496 ...` view save

user output
`468 605 825 532 496 ...` view save

Test 4

Subtask: 1, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`112 347 142 459 239 ...` view save

user output
`112 347 142 459 239 ...` view save

Test 5

Subtask: 1, 3, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`381 544 94 532 98 ...` view save

user output
`381 544 94 532 98 ...` view save

Test 6

Subtask: 1, 2, 4, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`133 73 81 82 53 ...` view save

user output
`133 73 81 82 53 ...` view save

Test 7

Subtask: 1, 2, 4, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`139 52 101 14 144 ...` view save

user output
`139 52 101 14 144 ...` view save

Test 8

Subtask: 1, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`236 555 878 632 829 ...` view save

user output
`236 555 878 632 829 ...` view save

Test 9

Subtask: 1, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`425 296 698 577 422 ...` view save

user output
`425 296 698 577 422 ...` view save

Test 10

Subtask: 1, 3, 4, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`1365 7284 11808 6136 9283 ...` view save

user output
`1365 7284 11808 6136 9283 ...` view save

Test 11

Subtask: 1, 3, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`6292 17954 16728 8938 1335 ...` view save

user output
`6292 17954 16728 8938 1335 ...` view save

Test 12

Subtask: 1, 4, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`27 141 269 127 61 ...` view save

user output
`27 141 269 127 61 ...` view save

Test 13

Subtask: 1, 3, 4, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`19552 19544 19478 19402 19456 ...` view save

user output
`19552 19544 19478 19402 19456 ...` view save

Test 14

Subtask: 1, 4, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`17624 17515 17468 17689 17510 ...` view save

user output
`17624 17515 17468 17689 17510 ...` view save

Test 15

Subtask: 1, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`1584 1433 567 2248 1030 ...` view save

user output
`1584 1433 567 2248 1030 ...` view save

Test 16

Subtask: 1, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`5872 6374 60 323 5311 ...` view save

user output
`5872 6374 60 323 5311 ...` view save

Test 17

Subtask: 1, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`1852 213 252 3861 1835 ...` view save

user output
`1852 213 252 3861 1835 ...` view save

Test 18

Subtask: 1, 5

Verdict: ACCEPTED

input
`200 200 .................................` view save

correct output
`1564 2709 866 1318 1758 ...` view save

user output
`1564 2709 866 1318 1758 ...` view save

Test 19

Subtask: 2, 4, 5

Verdict: WRONG ANSWER

input
`997 100000 .................................` view save

correct output
`150 531 370 518 508 ...` view save

user output
`150 235 108 518 30 ...` view save

Feedback: Incorrect character on line 2 col 1: expected "531", got "235"

Test 20

Subtask: 2, 4, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`390 278 783 1269 249 ...` view save

user output
`352 34 783 1269 249 ...` view save

Feedback: Incorrect character on line 1 col 2: expected "390", got "352"

Test 21

Subtask: 2, 4, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`63 142 813 683 731 ...` view save

user output
`0 0 0 0 0 ...` view save

Feedback: Incorrect character on line 1 col 1: expected "63", got "0"

Test 22

Subtask: 2, 4, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`949 876 1209 494 1033 ...` view save

user output
`949 382 739 382 697 ...` view save

Feedback: Incorrect character on line 2 col 1: expected "876", got "382"

Test 23

Subtask: 3, 5

Verdict: WRONG ANSWER

input
`997 100000 .................................` view save

correct output
`714 2683 3699 2085 7850 ...` view save

user output
`512 155 3061 2033 2450 ...` view save

Feedback: Incorrect character on line 1 col 1: expected "714", got "512"

Test 24

Subtask: 3, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`5081 1819 1050 4610 528 ...` view save

user output
`2117 1763 1046 1408 440 ...` view save

Feedback: Incorrect character on line 1 col 1: expected "5081", got "2117"

Test 25

Subtask: 3, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`3554 6322 6648 2882 1490 ...` view save

user output
`3346 4302 3990 202 978 ...` view save

Feedback: Incorrect character on line 1 col 2: expected "3554", got "3346"

Test 26

Subtask: 3, 5

Verdict: ACCEPTED

input
`1000 100000 .................................` view save

correct output
`433976 81646 87810 48080 110879 ...` view save

user output
`433976 81646 87810 48080 110879 ...` view save

Test 27

Subtask: 3, 4, 5

Verdict: ACCEPTED

input
`1000 100000 .................................` view save

correct output
`207982 140036 208364 51912 56826 ...` view save

user output
`207982 140036 208364 51912 56826 ...` view save

Test 28

Subtask: 3, 4, 5

Verdict: ACCEPTED

input
`1000 100000 .................................` view save

correct output
`497525 497563 498000 496804 497335 ...` view save

user output
`497525 497563 498000 496804 497335 ...` view save

Test 29

Subtask: 4, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`38580 2097 9795 38033 1639 ...` view save

user output
`38026 1011 9795 38033 1231 ...` view save

Feedback: Incorrect character on line 1 col 3: expected "38580", got "38026"

Test 30

Subtask: 4, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`33 20900 25028 1782 13599 ...` view save

user output
`33 20888 24862 1182 13385 ...` view save

Feedback: Incorrect character on line 2 col 3: expected "20900", got "20888"

Test 31

Subtask: 4, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`1421 1122 1840 834 443 ...` view save

user output
`827 1122 618 128 23 ...` view save

Feedback: Incorrect character on line 1 col 1: expected "1421", got "827"

Test 32

Subtask: 4, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`1378 1751 2274 250 811 ...` view save

user output
`1378 1091 1208 250 811 ...` view save

Feedback: Incorrect character on line 2 col 2: expected "1751", got "1091"

Test 33

Subtask: 4, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`1126 886 544 223 272 ...` view save

user output
`1126 140 240 189 264 ...` view save

Feedback: Incorrect character on line 2 col 1: expected "886", got "140"

Test 34

Subtask: 4, 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`327286 447779 447534 448307 446997 ...` view save

user output
`327286 447779 447534 448307 446997 ...` view save

Feedback: Incorrect character on line 8 col 4: expected "446902", got "446832"

Test 35

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`2597 1473 1933 2691 1837 ...` view save

user output
`2229 483 1183 2673 33 ...` view save

Feedback: Incorrect character on line 1 col 2: expected "2597", got "2229"

Test 36

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`553 4357 3147 6951 1573 ...` view save

user output
`295 1417 1131 5897 185 ...` view save

Feedback: Incorrect character on line 1 col 1: expected "553", got "295"

Test 37

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`1723 2039 1871 5638 4256 ...` view save

user output
`1445 1855 1509 3452 2396 ...` view save

Feedback: Incorrect character on line 1 col 2: expected "1723", got "1445"

Test 38

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`1546 704 2796 3802 1870 ...` view save

user output
`872 610 1524 1230 1232 ...` view save

Feedback: Incorrect character on line 1 col 1: expected "1546", got "872"

Test 39

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`3115 2042 2083 3227 740 ...` view save

user output
`3033 880 2081 509 726 ...` view save

Feedback: Incorrect character on line 1 col 2: expected "3115", got "3033"

Test 40

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`5222 3211 5230 1772 2310 ...` view save

user output
`5126 1945 4738 1402 1052 ...` view save

Feedback: Incorrect character on line 1 col 2: expected "5222", got "5126"

Test 41

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`159214 68851 200821 141404 145704 ...` view save

user output
`159214 68851 200821 141404 134816 ...` view save

Feedback: Incorrect character on line 5 col 2: expected "145704", got "134816"

Test 42

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`1843 25028 124430 84542 131339 ...` view save

user output
`1843 25028 124430 84542 131339 ...` view save

Feedback: Incorrect character on line 7 col 5: expected "18418", got "18414"

Test 43

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`111206 75799 12026 142133 20483 ...` view save

user output
`111206 75799 12026 142133 20483 ...` view save

Feedback: Incorrect character on line 7 col 4: expected "14564", got "14536"

Test 44

Subtask: 5

Verdict: WRONG ANSWER

input
`1000 100000 .................................` view save

correct output
`20360 9075 12187 54923 54574 ...` view save

user output
`20356 9073 12183 54921 54570 ...` view save

Feedback: Incorrect character on line 1 col 4: expected "20360", got "20356"

BOI 2026 Mirror Day 1

Island

Code

Test details

Test 1

Test 2

Test 3

Test 4

Test 5

Test 6

Test 7

Test 8

Test 9

Test 10

Test 11

Test 12

Test 13

Test 14

Test 15

Test 16

Test 17

Test 18

Test 19

Test 20

Test 21

Test 22

Test 23

Test 24

Test 25

Test 26

Test 27

Test 28

Test 29

Test 30

Test 31

Test 32

Test 33

Test 34

Test 35

Test 36

Test 37

Test 38

Test 39

Test 40

Test 41

Test 42

Test 43

Test 44

Tasks

Submissions (Mauricio_Cruz)