Submission #682305

#	Time	Username	Problem	Language	Result	Execution time	Memory
682305		vjudge1	Building 4 (JOI20_building4)	C++17	100 / 100	287 ms	68928 KiB

building4

#include<bits/stdc++.h>
#pragma GCC target("avx2")
#pragma GCC optimization("O3")
#pragma GCC optimization("unroll-loops")
#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
using namespace std;

#define int long long
#define ll long long
#define pb push_back
#define ppb pop_back
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define freopen(x) freopen(x".in","r",stdin);freopen(x".out","w",stdout);

const int N = 1000000 + 5;
const int M = 4000 + 5;
const ll mod = 1e9 + 7;
const ll inf = 1e17;

int n, a[N], b[N], mna[N], mxa[N], mnb[N], mxb[N], cnt;
string s;

void solve(){
    cin >> n;
    n *= 2;
    for(int i = 1; i <= n; i ++){
        cin >> a[i];
    }
    for(int i = 1; i <= n; i++){
        cin >> b[i];
    }
    for(int i = 1; i <= n; i++){
        mna[i] = inf;
        mnb[i] = inf;
        mxa[i] = -inf;
        mxb[i] = -inf;
    }
    for(int i = 1; i <= n; i++){
        if(a[i] >= a[i - 1]){
            mna[i] = mna[i - 1] + 1;
            mxa[i] = mxa[i - 1] + 1;
        }
        if(a[i] >= b[i - 1]){
            mna[i] = min(mna[i], mnb[i - 1] + 1);
            mxa[i] = max(mxa[i], mxb[i - 1] + 1);
        }
        if(b[i] >= a[i - 1]){
            mnb[i] = mna[i - 1];
            mxb[i] = mxa[i - 1];
        }
        if(b[i] >= b[i - 1]){
            mnb[i] = min(mnb[i], mnb[i - 1]);
            mxb[i] = max(mxb[i], mxb[i - 1]);
        }
    }
    char c = 'C';
    cnt = n / 2;
    if(mna[n] <= cnt && mxa[n] >= cnt){
        c = 'A';
        cnt--;
    }else if(mnb[n] <= cnt && mxb[n] >= cnt){
        c = 'B';
    }
    if(c == 'C'){
        cout << -1;
        return;
    }
    s += c;
    while(n > 1){
        if(c == 'A'){
            if(a[n] >= a[n - 1] && mna[n - 1] <= cnt && mxa[n - 1] >= cnt){
                c = 'A';
                cnt--;
            }else if(a[n] >= b[n - 1] && mnb[n - 1] <= cnt && mxb[n - 1] >= cnt){
                c = 'B';
            }
        }else{
            if(b[n] >= a[n - 1] && mna[n - 1] <= cnt && mxa[n - 1] >= cnt){
                c = 'A';
                cnt--;
            }else if(b[n] >= b[n - 1] && mnb[n - 1] <= cnt && mxb[n - 1] >= cnt){
                c = 'B';
            }
        }
        s += c;
        n--;
    }
    reverse(all(s));
    cout << s;
}


main() {
    fast
    int tt = 1;
    // cin >> tt;
    while(tt--){
        solve();
    }
}

Compilation message (stderr)

building4.cpp:3: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    3 | #pragma GCC optimization("O3")
      | 
building4.cpp:4: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    4 | #pragma GCC optimization("unroll-loops")
      | 
building4.cpp:5: warning: ignoring '#pragma comment ' [-Wunknown-pragmas]
    5 | #pragma comment(linker, "/stack:200000000")
      | 
building4.cpp:98:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   98 | main() {
      | ^~~~

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