Submission #531817

#	Time	Username	Problem	Language	Result	Execution time	Memory
531817		zxcvbnm	Dango Maker (JOI18_dango_maker)	C++14	100 / 100	562 ms	128320 KiB

dango_maker

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

constexpr int nax = 3005;
char mat[nax][nax];
const string str = "RGW";

/*
    0 - desine
    1 - virsus
*/

bool gali[nax][nax][2];
int n, m;
int dp[nax][3];

bool check_ok(int i, int j, int p) {
    if (i < 0 || j < 0 || i >= n || j >= m) return false;

    string curr;
    if (p == 0) {
        for(int k = 0; k < 3; k++) {
            curr += mat[i][j+k];
        }
    }
    else {
        for(int k = 0; k < 3; k++) {
            curr += mat[i+k][j];
        }
    }
    return (curr == str);
}

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

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> n >> m;

    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            cin >> mat[i][j];
        }
    }

    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            if (mat[i][j] == 'G') {
                if (j-1 >= 0) {
                    gali[i][j][0] = check_ok(i, j-1, 0);
                }
                if (i-1 >= 0) {
                    gali[i][j][1] = check_ok(i-1, j, 1);
                }
            }
        }
    }

    vector<pair<int, int>> s[nax+nax];

    for(int i = 0; i < n; i++) {
        for(int j = 0; j < m; j++) {
            s[i+j].push_back({i, j});
        }
    }

    int ans = 0;
    for(int sz = 0; sz < m+n; sz++) {
        for(const auto& p : s[sz]) {
            int i = p.first, j = p.second;
//            cout << "curr: " << i << " " << j << "\n";

            if (i) {
                dp[i][0] = max({dp[i-1][0], dp[i-1][1], dp[i-1][2]});
                if (gali[i][j][0]) {
                    dp[i][1] = max(dp[i-1][0], dp[i-1][1]) + 1;
                }
                if (gali[i][j][1]) {
                    dp[i][2] = max(dp[i-1][0], dp[i-1][2]) + 1;
                }
            }
            else {
                if (gali[i][j][0]) {
                    dp[i][1] = ans+1;
                }
                if (gali[i][j][1]) {
                    dp[i][2] = ans+1;
                }
            }

//            cout << i << " " << j << ":\n";
            for(int k = 0; k < 3; k++) {
                ans = max(ans, dp[i][k]);
//                cout << dp[i][k] << " ";
            }
//            cout << "\n";
        }
        for(int i = 0; i < n; i++) {
            dp[i][0] = ans;
        }
    }

    cout << ans << "\n";
    return 0;
}

• Subtask 1: 13 / 13
• Subtask 2: 20 / 20
• Subtask 3: 67 / 67