Submission #1039106

#	Time	Username	Problem	Language	Result	Execution time	Memory
1039106		coin_	Nafta (COI15_nafta)	C++14	100 / 100	241 ms	146000 KiB

nafta

#include <bits/stdc++.h>
#define int long long
using namespace std;

const int maxcol = 2003;
int dx[] = {1, -1, 0, 0};
int dy[] = {0, 0, -1, 1};
vector<vector<int>> id(maxcol, vector<int>(maxcol, 0)), cost(maxcol, vector<int>(maxcol, 0));

void calculatecostfunction(int col){
    for (int end = 1; end <= col; end++){
        for (int start = end; start >= 0; start--){
            cost[start][end] = cost[start+1][end] + id[start+1][end];
        }
    }
}

int l, r, totalcost = 0;
void dfs(int x, int y, vector<vector<char>> &board, int n, int m){
    totalcost += board[y][x] - '0';
    board[y][x] = '.';
    l = min(l, x);
    r = max(r, x);
    for (int i = 0; i < 4; i++){
        int tx = x + dx[i], ty = y + dy[i];
        if (tx <= 0 || ty <= 0 || tx > m || ty > n) continue;
        if (board[ty][tx] != '.'){
            dfs(tx, ty, board, n, m);
        }
    }
}

vector<int> dp_pre, dp_cur;
void dnc(int l, int r, int optl, int optr){
    if (l > r) return;
    int mid = (l + r)/2;

    pair<int, int> best = {-1, -1};
    for (int k = optl; k <= min(mid, optr); k++){
        best = max(best, {cost[k][mid] + dp_pre[k], k});
    }

    int opt = best.second;
    dp_cur[mid] = best.first;
    dnc(l, mid-1, optl, opt);
    dnc(mid+1, r, opt, optr);
}

signed main(){
    cin.tie(0) -> sync_with_stdio(0);
    int n, m;
    cin >> n >> m;
    vector<vector<char>> board(n+1, vector<char>(m+1));
    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= m; j++){
            cin >> board[i][j];
        }
    }
    for (int i = 1; i <= n; i++){
        for (int j = 1; j <= m; j++){
            if (board[i][j] != '.'){
                l = m + 1, r = 0, totalcost = 0;
                dfs(j, i, board, n, m);
                for (int ptr = l; ptr <= r; ptr++){
                    id[l][ptr] += totalcost;
                }
            }
        }
    }
    calculatecostfunction(m);
    
    dp_cur.assign(m+1, 0);
    dp_pre.assign(m+1, 0);
    for (int i = 1; i <= m; i++){
        dp_cur[i] = cost[0][i];
    }
    int mx = 0;
    for (int i = 1; i <= m; i++){
        mx = max(mx, dp_cur[i]);
    }
    cout << mx << endl;
    for (int i = 2; i <= m; i++){
        dp_pre = dp_cur;
        dnc(1, m, 1, m);
        mx = 0;
        for (int j = 1; j <= m; j++){
            mx = max(mx, dp_cur[j]);
        }
        cout << mx << endl;
    }
}

• Subtask 1: 11 / 11
• Subtask 2: 23 / 23
• Subtask 3: 66 / 66