Submission #1276348

#	Time	Username	Problem	Language	Result	Execution time	Memory
1276348		domi	Paint By Numbers (IOI16_paint)	C++20	100 / 100	834 ms	332508 KiB

paint

#include <bits/stdc++.h>
#include "paint.h"

// #define int long long
#define fi first
#define se second

#define sz(a) (int)((a).size())
#define all(a) (a).begin(), (a).end()

#define lsb(x) (x & (-x))
#define vi vector<int>
#define YES { cout << "YES" << endl; return; }
#define NO { cout << "NO" << endl; return; }

using ll = long long;
using pii = std::pair<int, int>;

using namespace std;

int n, k;

vector<vector<array<int, 2>>> get_dp(string s, vector<int> c) {
    vector<vector<array<int, 2>>> dp(n + 5, vector<array<int, 2>>(k + 1, {0, 0}));
    vector<int>pref(n + 5, 0);
    s = '$' + s;

    for (int i = 1; i <= n; ++i)
        pref[i] = pref[i - 1] + (s[i] == '_');

    auto alb = [&](int l, int r) -> int {
        return (pref[r] - pref[l - 1]) > 0;
    };

    dp[0][0][0] = 1;
    for (int i = 1; i <= n; ++i) {

        ///pun alb
        for (int j = 0; j <= k; ++j) {
            if (s[i] != 'X' && (dp[i - 1][j][0] || dp[i - 1][j][1]))
                dp[i][j][0] = 1;
        }

        for (int j = 1; j <= k; ++j) {
            int len = c[j - 1];
            int st = i - len + 1;

            if (st < 1 || alb(st, i) || (st > 1 && s[st - 1] == 'X')) continue;
            if (dp[st - 1][j - 1][0])
                dp[i][j][1] = 1;
        }
    }

    return dp;
}

string solve_puzzle(string s, vector<int> c) {
    n = sz(s);
    k = sz(c);

    auto sR = s; reverse(all(sR));
    auto cR = c; reverse(all(cR));

    auto dpL = get_dp(s, c);
    auto dpR = get_dp(sR, cR);

    auto get_dpR = [&](int i, int j, int c) -> int{
        int idx = n - i + 1;
        if (idx < 0 || idx > n) return 0;
        return dpR[idx][j][c];
    };

    s = '$' + s;
    vector<int>pref(n + 5, 0LL);
    for (int i = 1; i <= n; ++i)
        pref[i] = pref[i - 1] + (s[i] == '_');

    auto alb = [&](int l, int r) -> int {
        return (pref[r] - pref[l - 1]) > 0;
    };

    vector<int>canW(n + 5);
    for (int i = 1; i <= n; ++i) {
        if (s[i] == 'X') continue;

        for (int j = 0; j <= k && !canW[i]; ++j) {
            bool left = (dpL[i - 1][j][0] || dpL[i - 1][j][1]);
            bool right = (get_dpR(i + 1, k - j, 0) || get_dpR(i + 1, k - j, 1));

            if (left && right)
                canW[i] = 1;
        }
    }

    vector<int>mars(n + 5, 0);
    for (int j = 1; j <= k; ++j) {
        int len = c[j - 1];

        for (int st = 1; st + len - 1 <= n; ++st) {
            int dr = st + len - 1;

            if (alb(st, dr) || (st > 1 && s[st - 1] == 'X') || (dr < n && s[dr + 1] == 'X')) continue;

            if (dpL[st - 1][j - 1][0] && get_dpR(dr + 1, k - j, 0)) {
                ++mars[st];
                --mars[dr + 1];
            }
        }
    }

    string ans(n, '?');
    for (int i = 1; i <= n; ++i) {
        mars[i] += mars[i - 1];

        if (canW[i] && !mars[i])
            ans[i - 1] = '_';
        if (!canW[i] && mars[i])
            ans[i - 1] = 'X';
    }

    return ans;
}

// signed main() {
//     cin.tie(nullptr)->sync_with_stdio(false);
//     string s;
//     int k;
//     cin >> s >> k;
//     vector<int>c(k);
//     for (auto &it : c)
//         cin >> it;
//     cout << solve_puzzle(s, c);
//     return 0;
// }

Compilation message (stderr)

paint.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~
paint_c.h:1:9: warning: #pragma once in main file
    1 | #pragma once
      |         ^~~~

• Subtask 1: 7 / 7
• Subtask 2: 3 / 3
• Subtask 3: 22 / 22
• Subtask 4: 27 / 27
• Subtask 5: 21 / 21
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10