Submission #378431

#	Time	Username	Problem	Language	Result	Execution time	Memory
378431		MatheusLealV	Building 4 (JOI20_building4)	C++17	0 / 100	19 ms	31852 KiB

building4

#include <bits/stdc++.h>
#define pb push_back
#define all(x) begin(x), end(x)
using namespace std;
#define N 2000050
int n, v[2][N];
char t[2]={'A','B'};
int dpmin[N][2], dpmax[N][2];
int solve_min(int i, int flag){
	if(i == 0) return 0;
	if(dpmin[i][flag] != -1) return dpmin[i][flag];
	int ans=(int)(1e8);
	for(int c=0;c<2;c++)
		if(v[c][i] <= v[flag][i+1]) ans = min(ans, solve_min(i-1, c) + c);
	return dpmin[i][flag]=ans;
}
int solve_max(int i, int flag){
	if(i == 0) return 0;
	if(dpmax[i][flag] != -1) return dpmax[i][flag];
	int ans=-(int)(1e8);
	for(int c=0;c<2;c++)
		if(v[c][i] <= v[flag][i+1]) ans = max(ans, solve_max(i-1, c) + c);
	return dpmax[i][flag]=ans;
}
int main(){
	ios::sync_with_stdio(false); cin.tie(0);
	cin>>n;
	// if(n>3000)return 0;
	n *= 2;
	for(int i = 1; i <= n; i++) cin>>v[0][i];
	for(int i = 1; i <= n; i++) cin>>v[1][i];
	v[0][n+1] = v[1][n+1]=(int)(1e9);
	memset(dpmin,-1,sizeof dpmin);
	memset(dpmax,-1,sizeof dpmax);
	string s;
	int qb=n/2,ant=0, qa=n/2;
	// cout<<solve_min(n, 0)<<" "<<solve_max(n, 0)<<"\n";
	for(int i=n;i>=1;i--){
		if(solve_min(i, ant) <= qb and qb <= solve_max(i, ant)){
			//testa colocar A
			int mn1 = solve_min(i - 1, 0), mx1 = solve_max(i-1, 0);
			int mn2 = solve_min(i - 1, 1), mx2 = solve_max(i-1, 1);
			if(mn1 <= qb and qb <= mx1 and qa) s.pb('A'),ant=0, qa--;
			else s.pb('B'), qb--,ant=1;
		}
		else cout<<"-1\n", exit(0);
	}
	reverse(all(s));
	if(qb != 0 or qa != 0) cout<<"-1\n";
	else cout<<s<<"\n";
}

Compilation message (stderr)

building4.cpp: In function 'int main()':
building4.cpp:42:8: warning: unused variable 'mn2' [-Wunused-variable]
   42 |    int mn2 = solve_min(i - 1, 1), mx2 = solve_max(i-1, 1);
      |        ^~~
building4.cpp:42:35: warning: unused variable 'mx2' [-Wunused-variable]
   42 |    int mn2 = solve_min(i - 1, 1), mx2 = solve_max(i-1, 1);
      |                                   ^~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 89