Submission #949996

#	Time	Username	Problem	Language	Result	Execution time	Memory
949996		Abito	Chorus (JOI23_chorus)	C++17	16 / 100	40 ms	32240 KiB

chorus

#include <bits/stdc++.h>
#define F first
#define S second
#define pb push_back
#define ppb pop_back
#define ep insert
#define endl '\n'
#define elif else if
#define pow pwr
#define sqrt sqrtt
#define int long long
#define ll long long
typedef unsigned long long ull;
using namespace std;
const int N=21,M=2e6;
int dis[M],n,k;
char a[N];
void bfs(int s){
    dis[s]=0;
    queue<int> q;q.push(s);
    while (!q.empty()){
        int x=q.front();q.pop();
        for (int i=0;i<2*n-1;i++){
            if ((x&(1<<i)) && (x&(1<<(i+1)))) continue;
            if (!(x&(1<<i)) && !(x&(1<<(i+1)))) continue;
            int y=x;
            y^=(1<<i);
            y^=(1<<(i+1));
            if (dis[y]==-1) dis[y]=dis[x]+1,q.push(y);
        }
    }return;
}
bool check(int s){
    int x=0,y=0;
    bool vis[2*n]={0};
    for (int i=2*n-1;i>=0;i--){
        if (s&(1<<i)){
            x++;
            continue;
        }
        if (vis[i]) continue;
        y++;
        for (int j=i;j>=0 && x;j--){
            if (s&(1<<j)) continue;
            if (vis[j]) continue;
            vis[j]=1;x--;
        }
    }
    return y<=k && !x;
}
int32_t main(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    memset(dis,-1,sizeof(dis));
    cin>>n>>k;int mask=0;
    for (int i=0;i<2*n;i++){
        cin>>a[i];
        if (a[i]=='B') mask|=(1<<i);
    }
    bfs(mask);
    int ans=INT_MAX;
    for (int i=0;i<M;i++){
        if (dis[i]==-1) continue;
        if (check(i)) ans=min(ans,dis[i]);
    }cout<<ans<<endl;
    return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 0 / 24
• Subtask 3: 0 / 21
• Subtask 4: 0 / 26
• Subtask 5: 0 / 13