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Submission #625581

# Submission time Handle Problem Language Result Execution time Memory
625581 2022-08-10T15:16:48 Z I_love_Hoang_Yen Catfish Farm (IOI22_fish) C++17
53 / 100
 305 ms 19772 KB 
#include "bits/stdc++.h"
using namespace std;

#define int long long
struct Fish {
    int col, row;
    int weight;
};
bool operator < (const Fish& a, const Fish& b) {
    if (a.col != b.col) return a.col < b.col;
    return a.row < b.row;
}

// fishes are on even columns -> build piers on odd columns
// & catch all fishes
int sub1(const std::vector<Fish>& fishes) {
    int res = 0;
    for (const auto& fish : fishes) {
        res += fish.weight;
    }
    return res;
}

// fishes are on first 2 columns
int sub2(int n, const std::vector<Fish>& fishes) {
    std::vector<int> zeroes(n);  // prefix sum of fish weights at column == 0
    std::vector<int> ones(n);    // prefix sum of fish weights at column == 1
    for (const auto& fish : fishes) {
        if (fish.col == 0) zeroes[fish.row] += fish.weight;
        if (fish.col == 1) ones[fish.row] += fish.weight;
    }

    std::partial_sum(zeroes.begin(), zeroes.end(), zeroes.begin());
    std::partial_sum(ones.begin(), ones.end(), ones.begin());

    int res = ones.back();  // init: only catch fishes at column == 1
    for (int i = 0; i < n; ++i) {
        // build pier until at column 1, row 0-i
        if (n == 2) res = std::max(res, zeroes[i]);
        else res = std::max(res, zeroes[i] + ones.back() - ones[i]);
    }
    return res;
}

// all fishes are on row == 0
int sub3(int n, const std::vector<Fish>& fishes) {
    std::vector<int> weights(n);  // weights[i] = weight of fish at column i
    for (const auto& fish : fishes) {
        weights[fish.col] += fish.weight;
    }

    // f[i] = best strategy if we BUILD PIER AT i, only considering col 0..i
    // i-4 i-3 i-2 i-1 i
    std::vector<int> f(n);
    f[0] = 0;
    for (int i = 1; i < n; ++i) {
        f[i] = std::max(f[i-1], weights[i-1]);
        if (i >= 2) {
            f[i] = std::max(f[i], f[i-2] + weights[i-1]);
        }
        if (i >= 3) {
            f[i] = std::max(f[i], f[i-3] + weights[i-2] + weights[i-1]);
        }
    }

    int res = 0;
    for (int i = 0; i < n; ++i) {
        int cur = f[i];
        if (i + 1 < n) cur += weights[i+1];
        res = std::max(res, cur);
    }
    return res;
}

int sub5(int n, const std::vector<Fish>& fishes) {
    // Init weights[i][j] = sum of fish on column i, from row 0 -> row j
    std::vector<std::vector<int>> weights(n, std::vector<int> (n, 0));
    for (const auto& fish : fishes) {
        weights[fish.col][fish.row] += fish.weight;
    }
    for (int col = 0; col < n; ++col) {
        std::partial_sum(weights[col].begin(), weights[col].end(), weights[col].begin());
    }

    // f[c][r] = best strategy if we last BUILD PIER AT column c, row r
    // only considering fishes <= (c, r)
    std::vector<std::vector<int>> f(n, std::vector<int> (n, 0)),
                                  g(n, std::vector<int> (n, 0));
    // f <= g
    for (int c = 1; c < n; ++c) {
        for (int r = 0; r < n; ++r) {
            // this is first pier
            f[c][r] = g[c][r] = weights[c-1][r];

            // last pier at column i-1
            for (int lastRow = 0; lastRow < n; ++lastRow) {
                if (lastRow <= r) {
                    int cur = std::max(
                            f[c-1][lastRow] + weights[c-1][r] - weights[c-1][lastRow],
                            g[c-1][lastRow]);
                    f[c][r] = std::max(f[c][r], cur);
                    g[c][r] = std::max(g[c][r], cur);
                } else {
                    f[c][r] = std::max(f[c][r], g[c-1][lastRow]);
                    g[c][r] = std::max(
                            g[c][r],
                            g[c-1][lastRow] + weights[c][lastRow] - weights[c][r]);
                }
            }

            // last pier at column i-2
            if (c >= 2) {
                for (int lastRow = 0; lastRow < n; ++lastRow) {
                    int cur = g[c-2][lastRow] + weights[c-1][std::max(lastRow, r)];
                    f[c][r] = std::max(f[c][r], cur);
                    g[c][r] = std::max(g[c][r], cur);
                }
            }
            
            // last pier at column i-3
            if (c >= 3) {
                for (int lastRow = 0; lastRow < n; ++lastRow) {
                    int cur = g[c-3][lastRow] + weights[c-2][lastRow] + weights[c-1][r];
                    f[c][r] = std::max(f[c][r], cur);
                    g[c][r] = std::max(g[c][r], cur);
                }
            }
        }
    }

    int res = 0;
    for (int c = 0; c < n; ++c) {
        for (int r = 0; r < n; ++r) {
            assert(g[c][r] >= f[c][r]);
            int cur = g[c][r];
            if (c + 1 < n) {
                cur += weights[c+1][r];
            }
            res = std::max(res, cur);
        }
    }
    return res;
}

#undef int
long long max_weights(
        int n, int nFish,
        std::vector<int> xs,
        std::vector<int> ys,
        std::vector<int> ws) {
    std::vector<Fish> fishes;
    for (int i = 0; i < nFish; ++i) {
        fishes.push_back({xs[i], ys[i], ws[i]});
    }

    if (std::all_of(xs.begin(), xs.end(), [] (int x) { return x % 2 == 0; })) {
        return sub1(fishes);
    }
    if (*std::max_element(xs.begin(), xs.end()) <= 1) {
        return sub2(n, fishes);
    }
    if (*std::max_element(ys.begin(), ys.end()) == 0) {
        return sub3(n, fishes);
    }
    if (n <= 300) {
        return sub5(n, fishes);
    }
    return 0;
}

Subtask #1
3.0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 5312 KB Output is correct
2 Correct 30 ms 5824 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 94 ms 19676 KB Output is correct
6 Correct 95 ms 19772 KB Output is correct

Subtask #2
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 60 ms 10384 KB Output is correct
3 Correct 65 ms 11220 KB Output is correct
4 Correct 26 ms 5336 KB Output is correct
5 Correct 31 ms 5816 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 27 ms 5460 KB Output is correct
13 Correct 31 ms 6452 KB Output is correct
14 Correct 29 ms 5456 KB Output is correct
15 Correct 29 ms 6084 KB Output is correct
16 Correct 26 ms 5456 KB Output is correct
17 Correct 31 ms 6068 KB Output is correct

Subtask #3
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 2 ms 1748 KB Output is correct
3 Correct 24 ms 4136 KB Output is correct
4 Correct 14 ms 3660 KB Output is correct
5 Correct 32 ms 6468 KB Output is correct
6 Correct 28 ms 6448 KB Output is correct
7 Correct 29 ms 6456 KB Output is correct
8 Correct 29 ms 6440 KB Output is correct

Subtask #4
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 256 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 34 ms 852 KB Output is correct
10 Correct 277 ms 2548 KB Output is correct
11 Correct 39 ms 888 KB Output is correct
12 Correct 259 ms 2496 KB Output is correct
13 Correct 4 ms 340 KB Output is correct
14 Correct 267 ms 2388 KB Output is correct

Subtask #5
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 256 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 34 ms 852 KB Output is correct
10 Correct 277 ms 2548 KB Output is correct
11 Correct 39 ms 888 KB Output is correct
12 Correct 259 ms 2496 KB Output is correct
13 Correct 4 ms 340 KB Output is correct
14 Correct 267 ms 2388 KB Output is correct
15 Correct 286 ms 2448 KB Output is correct
16 Correct 5 ms 468 KB Output is correct
17 Correct 277 ms 4604 KB Output is correct
18 Correct 292 ms 4556 KB Output is correct
19 Correct 276 ms 4532 KB Output is correct
20 Correct 281 ms 4556 KB Output is correct
21 Correct 283 ms 4568 KB Output is correct
22 Correct 305 ms 6580 KB Output is correct
23 Correct 269 ms 2868 KB Output is correct
24 Correct 276 ms 3788 KB Output is correct
25 Correct 266 ms 2496 KB Output is correct
26 Correct 272 ms 2836 KB Output is correct

Subtask #6
0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 256 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 34 ms 852 KB Output is correct
10 Correct 277 ms 2548 KB Output is correct
11 Correct 39 ms 888 KB Output is correct
12 Correct 259 ms 2496 KB Output is correct
13 Correct 4 ms 340 KB Output is correct
14 Correct 267 ms 2388 KB Output is correct
15 Correct 286 ms 2448 KB Output is correct
16 Correct 5 ms 468 KB Output is correct
17 Correct 277 ms 4604 KB Output is correct
18 Correct 292 ms 4556 KB Output is correct
19 Correct 276 ms 4532 KB Output is correct
20 Correct 281 ms 4556 KB Output is correct
21 Correct 283 ms 4568 KB Output is correct
22 Correct 305 ms 6580 KB Output is correct
23 Correct 269 ms 2868 KB Output is correct
24 Correct 276 ms 3788 KB Output is correct
25 Correct 266 ms 2496 KB Output is correct
26 Correct 272 ms 2836 KB Output is correct
27 Incorrect 1 ms 468 KB 1st lines differ - on the 1st token, expected: '2999', found: '0'
28 Halted 0 ms 0 KB -

Subtask #7
0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 2 ms 1748 KB Output is correct
3 Correct 24 ms 4136 KB Output is correct
4 Correct 14 ms 3660 KB Output is correct
5 Correct 32 ms 6468 KB Output is correct
6 Correct 28 ms 6448 KB Output is correct
7 Correct 29 ms 6456 KB Output is correct
8 Correct 29 ms 6440 KB Output is correct
9 Incorrect 27 ms 5828 KB 1st lines differ - on the 1st token, expected: '99999', found: '0'
10 Halted 0 ms 0 KB -

Subtask #8
0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 5312 KB Output is correct
2 Correct 30 ms 5824 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 94 ms 19676 KB Output is correct
6 Correct 95 ms 19772 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 60 ms 10384 KB Output is correct
9 Correct 65 ms 11220 KB Output is correct
10 Correct 26 ms 5336 KB Output is correct
11 Correct 31 ms 5816 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 0 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 212 KB Output is correct
18 Correct 27 ms 5460 KB Output is correct
19 Correct 31 ms 6452 KB Output is correct
20 Correct 29 ms 5456 KB Output is correct
21 Correct 29 ms 6084 KB Output is correct
22 Correct 26 ms 5456 KB Output is correct
23 Correct 31 ms 6068 KB Output is correct
24 Correct 0 ms 212 KB Output is correct
25 Correct 2 ms 1748 KB Output is correct
26 Correct 24 ms 4136 KB Output is correct
27 Correct 14 ms 3660 KB Output is correct
28 Correct 32 ms 6468 KB Output is correct
29 Correct 28 ms 6448 KB Output is correct
30 Correct 29 ms 6456 KB Output is correct
31 Correct 29 ms 6440 KB Output is correct
32 Correct 0 ms 212 KB Output is correct
33 Correct 0 ms 212 KB Output is correct
34 Correct 1 ms 256 KB Output is correct
35 Correct 1 ms 212 KB Output is correct
36 Correct 0 ms 212 KB Output is correct
37 Correct 0 ms 212 KB Output is correct
38 Correct 0 ms 212 KB Output is correct
39 Correct 0 ms 212 KB Output is correct
40 Correct 34 ms 852 KB Output is correct
41 Correct 277 ms 2548 KB Output is correct
42 Correct 39 ms 888 KB Output is correct
43 Correct 259 ms 2496 KB Output is correct
44 Correct 4 ms 340 KB Output is correct
45 Correct 267 ms 2388 KB Output is correct
46 Correct 286 ms 2448 KB Output is correct
47 Correct 5 ms 468 KB Output is correct
48 Correct 277 ms 4604 KB Output is correct
49 Correct 292 ms 4556 KB Output is correct
50 Correct 276 ms 4532 KB Output is correct
51 Correct 281 ms 4556 KB Output is correct
52 Correct 283 ms 4568 KB Output is correct
53 Correct 305 ms 6580 KB Output is correct
54 Correct 269 ms 2868 KB Output is correct
55 Correct 276 ms 3788 KB Output is correct
56 Correct 266 ms 2496 KB Output is correct
57 Correct 272 ms 2836 KB Output is correct
58 Incorrect 1 ms 468 KB 1st lines differ - on the 1st token, expected: '2999', found: '0'
59 Halted 0 ms 0 KB -