Submission #321746

#	Time	Username	Problem	Language	Result	Execution time	Memory
321746		alextodoran	Bajka (COCI20_bajka)	C++17	70 / 70	7 ms	1152 KiB

bajka

/**
 ____ ____ ____ ____ ____
||a |||t |||o |||d |||o ||
||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|

**/

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int N_MAX = 302;
const int M_MAX = 302;

int n, m;

string a, b;

ll dp[M_MAX][N_MAX];

struct State
{
    int pref;
    int pos;
};

struct Path
{
    State s;
    ll len;
};

bool operator < (const Path &a, const Path &b)
{
    return a.len > b.len;
}

priority_queue <Path> pq;

bool visited[M_MAX][N_MAX];

int L[N_MAX], R[N_MAX];

map <char, int> mp;

void Dijkstra ()
{
    for(int i = 1; i <= n; i++)
        if(a[i] == b[1])
            pq.push(Path{State{1, i}, 0});
    while(pq.empty() == false)
    {
        Path p = pq.top();
        pq.pop();
        if(visited[p.s.pref][p.s.pos] == true)
            continue;
        visited[p.s.pref][p.s.pos] = true;
        dp[p.s.pref][p.s.pos] = p.len;
        if(p.s.pref == m)
            continue;
        if(p.s.pos > 1 && a[p.s.pos - 1] == b[p.s.pref + 1] && visited[p.s.pref + 1][p.s.pos - 1] == false)
            pq.push(Path{State{p.s.pref + 1, p.s.pos - 1}, p.len + 1});
        if(p.s.pos < n && a[p.s.pos + 1] == b[p.s.pref + 1] && visited[p.s.pref + 1][p.s.pos + 1] == false)
            pq.push(Path{State{p.s.pref + 1, p.s.pos + 1}, p.len + 1});
        int pos1 = L[p.s.pos];
        int pos2 = R[p.s.pos];
        if(pos1 != 0 && visited[p.s.pref][pos1] == false)
            pq.push(Path{State{p.s.pref, pos1}, p.len + abs(p.s.pos - pos1)});
        if(pos2 != 0 && visited[p.s.pref][pos2] == false)
            pq.push(Path{State{p.s.pref, pos2}, p.len + abs(p.s.pos - pos2)});
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> m;
    cin >> a >> b;
    a = " " + a;
    b = " " + b;
    for(int i = 1; i <= n; i++)
    {
        if(mp.find(a[i]) != mp.end())
            L[i] = mp[a[i]];
        mp[a[i]] = i;
    }
    mp.clear();
    for(int i = n; i >= 1; i--)
    {
        if(mp.find(a[i]) != mp.end())
            R[i] = mp[a[i]];
        mp[a[i]] = i;
    }
    mp.clear();
    Dijkstra();
    ll ans = LLONG_MAX;
    for(int i = 1; i <= n; i++)
        if(visited[m][i] == true)
            ans = min(ans, dp[m][i]);
    if(ans == LLONG_MAX)
        ans = -1;
    cout << ans << "\n";
    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 50 / 50