oj.uz

Submission #920648

# Submission time Handle Problem Language Result Execution time Memory
920648 2024-02-02T20:17:59 Z alexander707070 Building 4 (JOI20_building4) C++14
100 / 100
 320 ms 120884 KB 
#include<bits/stdc++.h>
#define MAXN 1000007
using namespace std;

const int inf=1e9;

int n,a[MAXN],b[MAXN],cnt,p[MAXN],l,r;
int dp[MAXN][2],dp2[MAXN][2];
bool li[MAXN][2],li2[MAXN][2];

queue<int> s;

string sol,sol2;

int ff(int pos,int last){
	if(pos==n+1)return 0;

	if(li[pos][last])return dp[pos][last];
	li[pos][last]=true;
	dp[pos][last]=-inf;

	int x=0;
	if(last==0)x=a[pos-1];
	else x=b[pos-1];

	if(a[pos]>=x){
		dp[pos][last]=max(dp[pos][last],ff(pos+1,0)+1);
	}

	if(b[pos]>=x){
		dp[pos][last]=max(dp[pos][last],ff(pos+1,1));
	}

	return dp[pos][last];
}

int ff2(int pos,int last){
	if(pos==n+1)return 0;

	if(li2[pos][last])return dp2[pos][last];
	li2[pos][last]=true;
	dp2[pos][last]=-inf;

	int x=0;
	if(last==0)x=a[pos-1];
	else x=b[pos-1];

	if(a[pos]>=x){
		dp2[pos][last]=max(dp2[pos][last],ff2(pos+1,0));
	}

	if(b[pos]>=x){
		dp2[pos][last]=max(dp2[pos][last],ff2(pos+1,1)+1);
	}

	return dp2[pos][last];
}

void solve(int pos,int last){
	if(pos==n+1)return;

	int x;
	if(last==0)x=a[pos-1];
	else x=b[pos-1];

	if(a[pos]>=x and ff(pos,last)==ff(pos+1,0)+1){
		sol+="A"; solve(pos+1,0); return;
	}else{
		sol+="B"; solve(pos+1,1); return;
	}
}

void solve2(int pos,int last){
	if(pos==n+1)return;

	int x;
	if(last==0)x=a[pos-1];
	else x=b[pos-1];

	if(b[pos]>=x and ff2(pos,last)==ff2(pos+1,1)+1){
		sol2+="B"; solve2(pos+1,1); return;
	}else{
		sol2+="A"; solve2(pos+1,0); return;
	}
}

bool vis[MAXN];

void bfs(int pos){

	if(pos>0 and !vis[pos-1] and sol[pos-1]=='A' and sol2[pos-1]=='B'){
		l=pos-1;
		if(b[l+1]>=p[l] and b[l+1]<=p[l+2]){
			s.push(pos-1);
			vis[pos-1]=true;
		}
	}

	if(pos<n-1 and !vis[pos+1] and sol[pos+1]=='A' and sol2[pos+1]=='B'){
		l=pos+1;
		if(b[l+1]>=p[l] and b[l+1]<=p[l+2]){
			s.push(pos+1);
			vis[pos+1]=true;
		}
	}

	if(pos>0 and !vis[pos-1] and sol[pos-1]=='B' and sol2[pos-1]=='A'){
		l=pos-1;
		if(a[l+1]>=p[l] and a[l+1]<=p[l+2]){
			s.push(pos-1);
			vis[pos-1]=true;
		}
	}

	if(pos<n-1 and !vis[pos+1] and sol[pos+1]=='B' and sol2[pos+1]=='A'){
		l=pos+1;
		if(a[l+1]>=p[l] and a[l+1]<=p[l+2]){
			s.push(pos+1);
			vis[pos+1]=true;
		}
	}
}

int main(){

	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);

	cin>>n;
	n*=2;
	for(int i=1;i<=n;i++){
		cin>>a[i];
	}
	for(int i=1;i<=n;i++){
		cin>>b[i];
	}

	if(ff(1,0)<0 or ff(1,0)<n/2 or ff2(1,0)<n/2){
		cout<<"-1\n";
		return 0;
	}

	cnt=ff(1,0);
	solve(1,0); solve2(1,0);

	for(int i=0;i<sol.size();i++){
		if(sol[i]=='A')p[i+1]=a[i+1];
		else p[i+1]=b[i+1];
	}
	p[n+1]=inf;

	for(int i=0;i<sol.size();i++){
		if(sol[i]=='A' and sol2[i]=='B'){
			if(b[i+1]>=p[i] and b[i+1]<=p[i+2]){
				s.push(i); vis[i]=true;
			}
		}

		if(sol[i]=='B' and sol2[i]=='A'){
			if(a[i+1]>=p[i] and a[i+1]<=p[i+2]){
				s.push(i); vis[i]=true;
			}
		}
	}

	while(cnt>n/2 and !s.empty()){
		if(sol[s.front()]=='A'){
			sol[s.front()]='B'; cnt--;
			p[s.front()+1]=b[s.front()+1];
		}else{
			sol[s.front()]='A'; cnt++;
			p[s.front()+1]=a[s.front()+1];
		}

		bfs(s.front());
		s.pop();
	}

	cout<<sol<<"\n";
	

	return 0;
}

Compilation message

building4.cpp: In function 'int main()':
building4.cpp:147:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  147 |  for(int i=0;i<sol.size();i++){
      |              ~^~~~~~~~~~~
building4.cpp:153:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  153 |  for(int i=0;i<sol.size();i++){
      |              ~^~~~~~~~~~~

Subtask #1
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 12636 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 12636 KB Output is correct
4 Correct 2 ms 12752 KB Output is correct
5 Correct 2 ms 8792 KB Output is correct
6 Correct 4 ms 13024 KB Output is correct
7 Correct 2 ms 12888 KB Output is correct
8 Correct 3 ms 12892 KB Output is correct
9 Correct 3 ms 12892 KB Output is correct
10 Correct 2 ms 12892 KB Output is correct
11 Correct 3 ms 13092 KB Output is correct
12 Correct 3 ms 12892 KB Output is correct
13 Correct 3 ms 13096 KB Output is correct
14 Correct 3 ms 13148 KB Output is correct
15 Correct 3 ms 12904 KB Output is correct
16 Correct 2 ms 10844 KB Output is correct
17 Correct 3 ms 13092 KB Output is correct
18 Correct 3 ms 12892 KB Output is correct
19 Correct 3 ms 12892 KB Output is correct
20 Correct 4 ms 13024 KB Output is correct
21 Correct 3 ms 12888 KB Output is correct
22 Correct 3 ms 13028 KB Output is correct
23 Correct 3 ms 12892 KB Output is correct
24 Correct 3 ms 13148 KB Output is correct
25 Correct 3 ms 12892 KB Output is correct
26 Correct 3 ms 12892 KB Output is correct
27 Correct 3 ms 13020 KB Output is correct
28 Correct 2 ms 12892 KB Output is correct
29 Correct 3 ms 13024 KB Output is correct
30 Correct 3 ms 12892 KB Output is correct
31 Correct 3 ms 13020 KB Output is correct
32 Correct 3 ms 12892 KB Output is correct
33 Correct 3 ms 12892 KB Output is correct

Subtask #2
89.0 / 89.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 12636 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 12636 KB Output is correct
4 Correct 2 ms 12752 KB Output is correct
5 Correct 2 ms 8792 KB Output is correct
6 Correct 4 ms 13024 KB Output is correct
7 Correct 2 ms 12888 KB Output is correct
8 Correct 3 ms 12892 KB Output is correct
9 Correct 3 ms 12892 KB Output is correct
10 Correct 2 ms 12892 KB Output is correct
11 Correct 3 ms 13092 KB Output is correct
12 Correct 3 ms 12892 KB Output is correct
13 Correct 3 ms 13096 KB Output is correct
14 Correct 3 ms 13148 KB Output is correct
15 Correct 3 ms 12904 KB Output is correct
16 Correct 2 ms 10844 KB Output is correct
17 Correct 3 ms 13092 KB Output is correct
18 Correct 3 ms 12892 KB Output is correct
19 Correct 3 ms 12892 KB Output is correct
20 Correct 4 ms 13024 KB Output is correct
21 Correct 3 ms 12888 KB Output is correct
22 Correct 3 ms 13028 KB Output is correct
23 Correct 3 ms 12892 KB Output is correct
24 Correct 3 ms 13148 KB Output is correct
25 Correct 3 ms 12892 KB Output is correct
26 Correct 3 ms 12892 KB Output is correct
27 Correct 3 ms 13020 KB Output is correct
28 Correct 2 ms 12892 KB Output is correct
29 Correct 3 ms 13024 KB Output is correct
30 Correct 3 ms 12892 KB Output is correct
31 Correct 3 ms 13020 KB Output is correct
32 Correct 3 ms 12892 KB Output is correct
33 Correct 3 ms 12892 KB Output is correct
34 Correct 153 ms 32320 KB Output is correct
35 Correct 269 ms 109876 KB Output is correct
36 Correct 272 ms 108624 KB Output is correct
37 Correct 300 ms 110548 KB Output is correct
38 Correct 269 ms 114360 KB Output is correct
39 Correct 252 ms 110900 KB Output is correct
40 Correct 269 ms 117584 KB Output is correct
41 Correct 295 ms 111544 KB Output is correct
42 Correct 294 ms 113660 KB Output is correct
43 Correct 280 ms 116812 KB Output is correct
44 Correct 291 ms 116840 KB Output is correct
45 Correct 283 ms 116932 KB Output is correct
46 Correct 271 ms 120884 KB Output is correct
47 Correct 259 ms 116816 KB Output is correct
48 Correct 265 ms 116928 KB Output is correct
49 Correct 260 ms 117792 KB Output is correct
50 Correct 286 ms 115988 KB Output is correct
51 Correct 290 ms 116156 KB Output is correct
52 Correct 228 ms 105808 KB Output is correct
53 Correct 223 ms 106056 KB Output is correct
54 Correct 230 ms 102336 KB Output is correct
55 Correct 226 ms 108080 KB Output is correct
56 Correct 320 ms 116068 KB Output is correct
57 Correct 258 ms 110928 KB Output is correct
58 Correct 262 ms 111440 KB Output is correct
59 Correct 256 ms 111156 KB Output is correct
60 Correct 240 ms 106448 KB Output is correct
61 Correct 241 ms 111968 KB Output is correct
62 Correct 233 ms 110524 KB Output is correct
63 Correct 240 ms 113336 KB Output is correct
64 Correct 264 ms 110340 KB Output is correct
65 Correct 240 ms 113404 KB Output is correct