oj.uz

Submission #384927

# Submission time Handle Problem Language Result Execution time Memory
384927 2021-04-02T16:43:20 Z SansPapyrus683 Robot (JOI21_ho_t4) C++17
100 / 100
 1183 ms 76324 KB 
#include <iostream>
#include <vector>
#include <queue>
#include <unordered_map>

using std::cout;
using std::endl;
using std::vector;
using std::pair;

// https://oj.uz/problem/view/JOI21_ho_t4 (input ommitted due to length)
int main() {
    int crossing_num;
    int road_num;
    std::cin >> crossing_num >> road_num;
    vector<std::unordered_map<int, vector<pair<int, int>>>> neighbors(crossing_num);
    vector<std::unordered_map<int, long long>> color_sums(crossing_num);
    for (int r = 0; r < road_num; r++) {
        int from;
        int to;
        int color;
        int change_cost;
        std::cin >> from >> to >> color >> change_cost;
        neighbors[--from][color].push_back({--to, change_cost});
        neighbors[to][color].push_back({from, change_cost});
        color_sums[from][color] += change_cost;
        color_sums[to][color] += change_cost;
    }

    vector<std::unordered_map<int, long long>> min_cost(crossing_num);
    min_cost[0][-1] = 0;
    // a "node" will be represented as a position and the last color change (-1 if no change) along with its cost
    std::priority_queue<pair<long long, pair<int, int>>> frontier;
    frontier.push({0, {0, -1}});
    while (!frontier.empty()) {
        auto [at, debt_c] = frontier.top().second;
        long long curr_cost = min_cost[at][debt_c];
        if (-frontier.top().first != curr_cost) {
            frontier.pop();
            continue;
        }
        frontier.pop();
        if (debt_c == -1) {
            for (auto const& [c, n_list] : neighbors[at]) {
                for (auto [n, n_cost] : n_list) {
                    long long flip_others = curr_cost + color_sums[at][c] - n_cost;
                    if (!min_cost[n].count(-1) || flip_others < min_cost[n][-1]) {
                        min_cost[n][-1] = flip_others;
                        frontier.push({-flip_others, {n, -1}});
                    }
                    long long flip_this = curr_cost + n_cost;
                    if (flip_this < min_cost[n][-1]) {  // no membership check needed
                        min_cost[n][-1] = flip_this;
                        frontier.push({-flip_this, {n, -1}});
                    }
                    long long no_change = curr_cost;
                    if (!min_cost[n].count(c) || no_change < min_cost[n][c]) {
                        min_cost[n][c] = no_change;
                        frontier.push({-no_change, {n, c}});
                    }
                }
            }
        } else {
            for (auto [n, n_cost] : neighbors[at][debt_c]) {
                long long flip_others = curr_cost + color_sums[at][debt_c] - n_cost;
                if (!min_cost[n].count(-1) || flip_others < min_cost[n][-1]) {
                    min_cost[n][-1] = flip_others;
                    frontier.push({-flip_others, {n, -1}});
                }
            }
        }
    }
    cout << (!min_cost[crossing_num - 1].count(-1) ? -1 : min_cost[crossing_num - 1][-1]) << endl;
}

Subtask #1
34.0 / 34.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 2 ms 384 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 3 ms 492 KB Output is correct
8 Correct 2 ms 364 KB Output is correct
9 Correct 6 ms 1004 KB Output is correct
10 Correct 6 ms 1004 KB Output is correct
11 Correct 5 ms 876 KB Output is correct
12 Correct 5 ms 876 KB Output is correct
13 Correct 5 ms 876 KB Output is correct
14 Correct 5 ms 876 KB Output is correct
15 Correct 4 ms 748 KB Output is correct
16 Correct 6 ms 876 KB Output is correct
17 Correct 5 ms 748 KB Output is correct
18 Correct 2 ms 620 KB Output is correct
19 Correct 5 ms 492 KB Output is correct
20 Correct 5 ms 748 KB Output is correct

Subtask #2
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 374 ms 20832 KB Output is correct
2 Correct 132 ms 11512 KB Output is correct
3 Correct 431 ms 15840 KB Output is correct
4 Correct 211 ms 15840 KB Output is correct
5 Correct 1086 ms 74304 KB Output is correct
6 Correct 967 ms 68168 KB Output is correct
7 Correct 737 ms 56008 KB Output is correct
8 Correct 722 ms 50028 KB Output is correct
9 Correct 724 ms 50028 KB Output is correct
10 Correct 583 ms 36748 KB Output is correct
11 Correct 244 ms 29932 KB Output is correct

Subtask #3
42.0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 364 KB Output is correct
2 Correct 1 ms 364 KB Output is correct
3 Correct 1 ms 364 KB Output is correct
4 Correct 1 ms 364 KB Output is correct
5 Correct 2 ms 384 KB Output is correct
6 Correct 1 ms 364 KB Output is correct
7 Correct 3 ms 492 KB Output is correct
8 Correct 2 ms 364 KB Output is correct
9 Correct 6 ms 1004 KB Output is correct
10 Correct 6 ms 1004 KB Output is correct
11 Correct 5 ms 876 KB Output is correct
12 Correct 5 ms 876 KB Output is correct
13 Correct 5 ms 876 KB Output is correct
14 Correct 5 ms 876 KB Output is correct
15 Correct 4 ms 748 KB Output is correct
16 Correct 6 ms 876 KB Output is correct
17 Correct 5 ms 748 KB Output is correct
18 Correct 2 ms 620 KB Output is correct
19 Correct 5 ms 492 KB Output is correct
20 Correct 5 ms 748 KB Output is correct
21 Correct 374 ms 20832 KB Output is correct
22 Correct 132 ms 11512 KB Output is correct
23 Correct 431 ms 15840 KB Output is correct
24 Correct 211 ms 15840 KB Output is correct
25 Correct 1086 ms 74304 KB Output is correct
26 Correct 967 ms 68168 KB Output is correct
27 Correct 737 ms 56008 KB Output is correct
28 Correct 722 ms 50028 KB Output is correct
29 Correct 724 ms 50028 KB Output is correct
30 Correct 583 ms 36748 KB Output is correct
31 Correct 244 ms 29932 KB Output is correct
32 Correct 335 ms 10348 KB Output is correct
33 Correct 364 ms 16484 KB Output is correct
34 Correct 771 ms 36316 KB Output is correct
35 Correct 584 ms 29928 KB Output is correct
36 Correct 609 ms 48216 KB Output is correct
37 Correct 679 ms 49748 KB Output is correct
38 Correct 783 ms 56268 KB Output is correct
39 Correct 392 ms 14488 KB Output is correct
40 Correct 742 ms 51436 KB Output is correct
41 Correct 824 ms 51436 KB Output is correct
42 Correct 914 ms 55388 KB Output is correct
43 Correct 381 ms 21216 KB Output is correct
44 Correct 810 ms 22500 KB Output is correct
45 Correct 624 ms 48952 KB Output is correct
46 Correct 526 ms 48236 KB Output is correct
47 Correct 645 ms 50000 KB Output is correct
48 Correct 1183 ms 76324 KB Output is correct