Submission #469773

#	Time	Username	Problem	Language	Result	Execution time	Memory
469773		CodeChamp_SS	Tracks in the Snow (BOI13_tracks)	C++17	78.13 / 100	2093 ms	79300 KiB

tracks

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace std;

#define ff                  first
#define ss                  second
#define pb                  push_back
#define eb                  emplace_back
#define mp                  make_pair
#define lb                  lower_bound
#define ub                  upper_bound
#define setbits(x)          __builtin_popcountll(x)
#define zrobits(x)          __builtin_ctzll(x)
#define sz(v)               (int)v.size()
#define ps(y)               cout << fixed << setprecision(y)
#define ms(arr, v)          memset(arr, v, sizeof(arr))
#define all(v)              v.begin(), v.end()
#define rall(v)             v.rbegin(), v.rend()
#define trav(x, v)          for(auto &x: v)
#define w(t)                int t; cin >> t; while(t--)
#define rep(i, a, b)        for(int i = a; i <= b; i++)
#define rrep(i, a, b)       for(int i = a; i >= b; i--)
#define rep0(i, n)          rep(i, 0, n - 1)
#define rrep0(i, n)         rrep(i, n - 1, 0)
#define rep1(i, n)          rep(i, 1, n)
#define rrep1(i, n)         rrep(i, n, 1)
#define inp(arr, n)         rep0(i, n) cin >> arr[i];

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef vector<pii> vp;
typedef vector<bool> vb;
typedef vector<string> vs;
typedef map<ll, ll> mii;
typedef map<char, ll> mci;
typedef priority_queue<ll> pq_mx;
typedef priority_queue<ll, vi, greater<>> pq_mn;
typedef tree<ll, null_type, less<>, rb_tree_tag, tree_order_statistics_node_update> pbds;
/*
 * find_by_order(i) -> returns an iterator to the element at ith position (0 based)
 * order_of_key(i)  -> returns the position of element i (0 based)
 */

const int N = 4e3 + 5;
const int mod = 1e9 + 7;
//const int mod = 998244353;
const ll inf = 1e18;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void fio() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
}

int n, m, dist[N][N];
char a[N][N];

int dx[] = {-1, 1, 0, 0};
int dy[] = {0, 0, -1, 1};

bool valid(int x, int y) {
    return x >= 0 and y >= 0 and x < n and y < m;
}

int main() {
    fio();

    cin >> n >> m;
    rep0(x, n) inp(a[x], m)

    queue<pii> q;
    rep0(x, n) {
        rep0(y, m) dist[x][y] = 1e9;
    }
    q.emplace(0, 0), dist[0][0] = 0;
    while (!q.empty()) {
        auto[i, j] = q.front();
        q.pop();
        rep0(d, 4) {
            int x = i + dx[d], y = j + dy[d];
            if (valid(x, y) and a[x][y] != '.') {
                int l = 0;
                if (a[x][y] != a[i][j]) l = 1;
                if (dist[x][y] > l + dist[i][j]) {
                    dist[x][y] = l + dist[i][j];
                    q.emplace(x, y);
                }
            }
        }
    }
    int mx = 0;
    rep0(x, n) {
        rep0(y, m) {
            if (dist[x][y] != 1e9) mx = max(mx, dist[x][y]);
        }
    }
    cout << 1 + mx;


    return 0;
}

• Subtask 1: 30 / 30
• Subtask 2: 48.125 / 70