Submission #998784

#	Time	Username	Problem	Language	Result	Execution time	Memory
998784		snpmrnhlol	Building 4 (JOI20_building4)	C++17	0 / 100	3 ms	2504 KiB

building4

#include<bits/stdc++.h>
using namespace std;
const int N = 5e5;
const int inf = 2e9;
struct xy{
    int x,y;
}v[N];
bool ans[N];
int main(){
    bool ok = 1;
    int prv = -1;
    int cnt = 0;
    int n;
    cin>>n;
    for(int i = 0;i < 2*n;i++){
        cin>>v[i].x;
    }
    for(int i = 0;i < 2*n;i++){
        cin>>v[i].y;
    }
    for(int i = 0;i < 2*n;i++){
        if(v[i].x <= v[i].y){
            ///v[i].x
            if(prv <= v[i].x){
                ans[i] = 0;
                prv = v[i].x;
            }else if(prv <= v[i].y){
                ans[i] = 1;
                prv = v[i].y;
                cnt++;
            }else ok = 0;
        }else{
            if(prv <= v[i].y){
                ans[i] = 1;
                prv = v[i].y;
                cnt++;
            }else if(prv <= v[i].x){
                ans[i] = 0;
                prv = v[i].x;
            }else ok = 0;
        }
        prv = (ans[i] == 0?v[i].x:v[i].y);
    }
    if(cnt == n && ok){
        for(int i = 0;i < 2*n;i++){
            cout<<(ans[i] == 0?"A":"B");
        }
        return 0;
    }
    prv = inf;
    for(int i = 2*n - 1;i >= 0;i--){
        cnt-=ans[i];
        if(v[i].x <= v[i].y){
            if(prv >= v[i].y){
                ans[i] = 1;
                prv = v[i].y;
            }else if(prv >= v[i].x){
                ans[i] = 0;
                prv = v[i].x;
            }else ok = 0;
        }else{
            if(prv >= v[i].x){
                ans[i] = 0;
                prv = v[i].x;
            }else if(prv >= v[i].y){
                ans[i] = 1;
                prv = v[i].y;
            }else ok = 0;
        }
        cnt+=ans[i];
        prv = (ans[i] == 0?v[i].x:v[i].y);
        if(cnt == n && ok){
            for(int i = 0;i < 2*n;i++){
                cout<<(ans[i] == 0?"A":"B");
            }
            return 0;
        }
    }
    cout<<-1;
    return 0;
}

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