Submission #1099297

#	Time	Username	Problem	Language	Result	Execution time	Memory
1099297		theSkeleton	Tracks in the Snow (BOI13_tracks)	C++17	34.58 / 100	2134 ms	1048576 KiB

tracks

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include<bits/stdc++.h>
#define space <<' '<<
#define endl '\n'
#define inf 1e14
#define F first
#define S second
#define PB push_back
#define PF push_front
#define md(a) ((a+mod)%mod)
#define MP(a,b) make_pair(a,b)
#define MT(a,b,c) make_tuple(a,b,c)
typedef long long ll;
using namespace std;
template<typename t> using heap=
priority_queue<t,vector<t>,greater<t>>;
const int mx = 4e3+5;
deque<pair<int,int>> b;
deque<pair<int,int>> g;
char state[mx][mx];
bool seen[mx][mx];
int h,w;
bool c(int i,int j,char s){
    if(i<0||h<=i) return 1;
    if(j<0||w<=j) return 1;
    if(seen[i][j])return 1;
    if(state[i][j]==s){
        g.push_front(MP(i,j));
        return 1;
    }
    if (state[i][j]=='.')
        return 1;
    return 0;
}
int main(){
    std::ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    cin>>h>>w;
    for(int i=0;i<h;i++)
    for(int j=0;j<w;j++)
        cin>>state[i][j];
    int cnt=0;
    g.PB(MP(h-1,w-1));
    char cc=state[h-1][w-1];
    while((!g.empty())||(!b.empty())){
        cnt++;
        while(!b.empty()){
            auto p=b.back();
            b.pop_back();
            c(p.F+1,p.S,cc);
            c(p.F-1,p.S,cc);
            c(p.F,p.S+1,cc);
            c(p.F,p.S-1,cc);
        }
        while(!g.empty()){
            auto p=g.back();
            g.pop_back();
            bool k=1;
            seen[p.F][p.S]=1;
            k&=c(p.F+1,p.S,cc);
            k&=c(p.F-1,p.S,cc);
            k&=c(p.F,p.S+1,cc);
            k&=c(p.F,p.S-1,cc);
            if(!k)
                b.push_front(p);
        }
        cc=((cc=='F')?'R':'F');
    }
    cout<<cnt;
    return 0;
}

• Subtask 1: 8.333333333333334 / 30
• Subtask 2: 26.25 / 70