Submission #792966

#	Time	Username	Problem	Language	Result	Execution time	Memory
792966		tr1ten	Tracks in the Snow (BOI13_tracks)	C++14	100 / 100	437 ms	123868 KiB

tracks

#include <cstdio>
#include <bits/stdc++.h>

using namespace std;
#include "ext/pb_ds/assoc_container.hpp"
#include "ext/pb_ds/tree_policy.hpp"
using namespace __gnu_pbds;
template<class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update> ;
template<typename T> 
using ordered_multiset = tree<T, null_type,less_equal<T>, rb_tree_tag,tree_order_statistics_node_update>;
// find_by_order(k)  returns iterator to kth element starting from 0;
// order_of_key(k) returns count of elements strictly smaller than k;
// useful defs
typedef long long ll; 
typedef vector<ll> vi;
typedef vector<vi> vii;
typedef pair<ll,ll> pi;
typedef vector<pi> vpi;
typedef unordered_map<ll,ll> mll;
#define pb push_back
#define mp make_pair
#define rep(i,a,b) for (int i = (a); i < (b); i++)
#define per(i,a,b) for (int i = (b)-1; i >= (a); i--)
#define trav(a,arr) for (auto& a: (arr))
#define sz(x) (int)(x).size()
#define mk_vec(name,sz,value) vi name(sz,value)
#define mk_mat(name,n,m,value) vii name(n, vi(m, value))
#define contains(x) find(x) != string::npos
#define tkv(vec,sz) rep(i,0,sz) cin>>vec[i]
#define srv(vec) sort(vec.begin(), vec.end())
#define all(x) x.begin(), x.end()
#define less(a,b) a<b
#define vsum(vec) accumulate(vec.begin(), vec.end(), 0L);
#define vmax(vec) *max_element(vec.begin(), vec.end());
#define vmin(vec) *min_element(vec.begin(), vec.end());
#define pvc(vec) trav(x,vec) cout<<x<<" "; cout<<endl;
#define put(x) cout<<(x)<<endl;
#define put2(x,y) cout<<(x)<<" "<<(y)<<endl;
#define put3(x,y,z) cout<<(x)<<" "<<(y)<<" "<<(z)<<endl;
#define mod(x) (x + MOD)%MOD
// debugging
#define timed(x) {auto start = chrono::steady_clock::now(); x; auto end = chrono::steady_clock::now(); auto diff = end - start; cout << chrono::duration <double, milli> (diff).count() << " ms" << endl;}


void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}

#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
const ll MOD = 1e9+7;
const ll INF = 1e10+5;

// driver code
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    // freopen("input.in","r",stdin);
    // freopen("output.out","w",stdout);	  
    int T=1;
    // cin>>T;
    while(T--){
        int h,w;
        cin >> h >> w;
        string mat[h];
        rep(i,0,h){
            cin >> mat[i];
        }
        deque<pair<int,int>> q;
        q.push_back({0,0});
        int depth[h][w];
        memset(depth,0,sizeof depth);
        depth[0][0] = 1;
        int ans = 1;
        int dx[4]{1, -1, 0, 0}, dy[4]{0, 0, 1, -1};
        while (!q.empty())
        {
            auto p = q.front();
            q.pop_front();
            ans = max(ans,depth[p.first][p.second]);
            rep(i,0,4){
                int x=p.second+dx[i],y=p.first+dy[i];
                if(x<w && y<h && x>=0 && y>=0 && depth[y][x]==0 && mat[y][x]!='.'){
                    depth[y][x] = depth[p.first][p.second] + (mat[y][x] != mat[p.first][p.second]);
                    if(mat[y][x] != mat[p.first][p.second]) q.push_back({y,x});
                    else  q.push_front({y,x});
                }
            }
        }
        put(ans);
        
    }
    return 0;
}

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