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Submission #172618

# Submission time Handle Problem Language Result Execution time Memory
172618 2020-01-02T08:19:26 Z rama_pang Bridges (APIO19_bridges) C++14
100 / 100
 2565 ms 7316 KB 
#include <bits/stdc++.h>
using namespace std;
const int BLOCK = 900;

struct RollbackDSU {
    vector<int> root; // parent
    vector<int> sz; // size
    vector<pair<int, int>> operations; // (modified_id, size[id]). If size[id] == -1, then the parent changes

    void init(int n) {
        sz.assign(n, 1);
        root.assign(n, 0);
        iota(begin(root), end(root), 0);
    }

    int find(int n) {
        while (root[n] != n) {
            n = root[n];
        }
        return n;
    }

    bool join(int a, int b, bool revert = false) {
        a = find(a);
        b = find(b);
        if (a == b) {
            return false;
        }
        if (sz[a] < sz[b]) {
            swap(a, b);
        }
        if (revert) {
            operations.emplace_back(b, -1); // b's parent changes
            operations.emplace_back(a, sz[a]); // a's previous size
        }
        sz[a] += sz[b];
        root[b] = a;
        return true;
    }

    void rollback() {
        reverse(begin(operations), end(operations));
        for (auto& op : operations) {
            if (op.second == -1) {
                root[op.first] = op.first;
            } else {
                sz[op.first] = op.second;
            }
        }
        operations.clear();
    }
    
    int getSize(int n) {
        return sz[find(n)];
    }

};

struct Edge {
    int u, v, weight;
    Edge(int u, int v, int w) : u(u), v(v), weight(w) {}
    bool operator<(const Edge& o) const {
        return weight > o.weight;
    }
};

struct Query {
    int start, weight, time;
    Query(int s, int w, int t) : start(s), weight(w), time(t) {}
    bool operator<(const Query& o) const {
        return weight > o.weight;
    }
};

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);

    int n, m;
    cin >> n >> m;

    vector<Edge> edge;
    vector<pair<int, int>> update(m, make_pair(-1, -1)); // (weight, update_time)

    for (int i = 0; i < m; i++) {
        int u, v, w;
        cin >> u >> v >> w;
        u--, v--;
        edge.emplace_back(u, v, w);
    }

    int q;
    cin >> q;

    RollbackDSU DSU;
    vector<pair<int, int>> ans; // (time, answer)

    for (int qi = 0; qi < q; qi += BLOCK) {
        vector<Query> query; // query: (time, start, weight)
        vector<tuple<int, int, int, int>> changed; // (id, weight, time1, time2) -> the id-th edge has weight for time peirod [time1, time2]
        vector<Edge> unchanged; // ids of unchanged edges

        DSU.init(n);

        for (int i = qi; i < qi + BLOCK && i < q; i++) {
            int t, a, b;
            cin >> t >> a >> b;
            a--;

            if (t == 1) {
                if (update[a] == make_pair(-1, -1)) {
                    update[a].first = edge[a].weight;
                }
                changed.emplace_back(a, update[a].first, update[a].second, i - 1); // the current weight lasts between (t1, t2)
                update[a] = {b, i};
            } else if (t == 2) {
                query.emplace_back(a, b, i);
            }
        }

        for (int i = 0; i < m; i++) {
            if (update[i] != make_pair(-1, -1)) {
                changed.emplace_back(i, update[i].first, update[i].second, qi + BLOCK);

                // Update original edge's weight with latest update
                edge[i].weight = update[i].first;
                update[i] = make_pair(-1, -1);
            } else {
                unchanged.emplace_back(edge[i]);
            }
        }

        sort(begin(unchanged), end(unchanged));
        sort(begin(query), end(query));

        for (int i = 0, j = 0; i < query.size(); i++) { // O(BLOCK) iterations
            while (j < unchanged.size() && unchanged[j].weight >= query[i].weight) {
                DSU.join(unchanged[j].u, unchanged[j].v);
                j++;
            }

            for (auto& c : changed) { // O(BLOCK log n)
                int id, w, t1, t2;
                tie(id, w, t1, t2) = c;
                if (t1 <= query[i].time && query[i].time <= t2 && w >= query[i].weight) {
                    DSU.join(edge[id].u, edge[id].v, true);
                }
            }

            ans.emplace_back(query[i].time, DSU.getSize(query[i].start));
            DSU.rollback();
        }
    }


    sort(begin(ans), end(ans));
    for (auto& i : ans) {
        cout << i.second << "\n";
    }

    return 0;
}

Compilation message

bridges.cpp: In function 'int main()':
bridges.cpp:136:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0, j = 0; i < query.size(); i++) { // O(BLOCK) iterations
                                ~~^~~~~~~~~~~~~~
bridges.cpp:137:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             while (j < unchanged.size() && unchanged[j].weight >= query[i].weight) {
                    ~~^~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 256 KB Output is correct
2 Correct 2 ms 252 KB Output is correct
3 Correct 40 ms 504 KB Output is correct
4 Correct 7 ms 632 KB Output is correct
5 Correct 17 ms 504 KB Output is correct
6 Correct 18 ms 504 KB Output is correct
7 Correct 20 ms 504 KB Output is correct
8 Correct 21 ms 504 KB Output is correct
9 Correct 22 ms 504 KB Output is correct
10 Correct 22 ms 504 KB Output is correct
11 Correct 22 ms 504 KB Output is correct
12 Correct 24 ms 504 KB Output is correct
13 Correct 29 ms 504 KB Output is correct
14 Correct 27 ms 504 KB Output is correct
15 Correct 24 ms 636 KB Output is correct
16 Correct 21 ms 504 KB Output is correct
17 Correct 21 ms 504 KB Output is correct

Subtask #2
16.0 / 16.0

# Verdict Execution time Memory Grader output
1 Correct 1480 ms 3876 KB Output is correct
2 Correct 1509 ms 3888 KB Output is correct
3 Correct 1507 ms 3992 KB Output is correct
4 Correct 1605 ms 3972 KB Output is correct
5 Correct 1599 ms 3976 KB Output is correct
6 Correct 2418 ms 4200 KB Output is correct
7 Correct 2561 ms 4076 KB Output is correct
8 Correct 2476 ms 4244 KB Output is correct
9 Correct 51 ms 1508 KB Output is correct
10 Correct 1318 ms 3968 KB Output is correct
11 Correct 1229 ms 4256 KB Output is correct
12 Correct 1228 ms 4420 KB Output is correct
13 Correct 1511 ms 3608 KB Output is correct

Subtask #3
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 1179 ms 2804 KB Output is correct
2 Correct 895 ms 1456 KB Output is correct
3 Correct 1371 ms 2820 KB Output is correct
4 Correct 1164 ms 2904 KB Output is correct
5 Correct 51 ms 1636 KB Output is correct
6 Correct 1328 ms 2732 KB Output is correct
7 Correct 1093 ms 2648 KB Output is correct
8 Correct 946 ms 2692 KB Output is correct
9 Correct 718 ms 3400 KB Output is correct
10 Correct 658 ms 3108 KB Output is correct
11 Correct 830 ms 2564 KB Output is correct
12 Correct 726 ms 2476 KB Output is correct

Subtask #4
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1610 ms 7212 KB Output is correct
2 Correct 50 ms 1508 KB Output is correct
3 Correct 204 ms 5184 KB Output is correct
4 Correct 122 ms 5184 KB Output is correct
5 Correct 993 ms 7180 KB Output is correct
6 Correct 1589 ms 7164 KB Output is correct
7 Correct 973 ms 7264 KB Output is correct
8 Correct 827 ms 4400 KB Output is correct
9 Correct 851 ms 4356 KB Output is correct
10 Correct 826 ms 4472 KB Output is correct
11 Correct 1246 ms 6232 KB Output is correct
12 Correct 1215 ms 6368 KB Output is correct
13 Correct 1258 ms 6460 KB Output is correct
14 Correct 919 ms 7316 KB Output is correct
15 Correct 975 ms 7268 KB Output is correct
16 Correct 1624 ms 7212 KB Output is correct
17 Correct 1632 ms 7124 KB Output is correct
18 Correct 1642 ms 7148 KB Output is correct
19 Correct 1616 ms 7056 KB Output is correct
20 Correct 1389 ms 6784 KB Output is correct
21 Correct 1389 ms 6764 KB Output is correct
22 Correct 1589 ms 7128 KB Output is correct
23 Correct 957 ms 6612 KB Output is correct

Subtask #5
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1480 ms 3876 KB Output is correct
2 Correct 1509 ms 3888 KB Output is correct
3 Correct 1507 ms 3992 KB Output is correct
4 Correct 1605 ms 3972 KB Output is correct
5 Correct 1599 ms 3976 KB Output is correct
6 Correct 2418 ms 4200 KB Output is correct
7 Correct 2561 ms 4076 KB Output is correct
8 Correct 2476 ms 4244 KB Output is correct
9 Correct 51 ms 1508 KB Output is correct
10 Correct 1318 ms 3968 KB Output is correct
11 Correct 1229 ms 4256 KB Output is correct
12 Correct 1228 ms 4420 KB Output is correct
13 Correct 1511 ms 3608 KB Output is correct
14 Correct 1179 ms 2804 KB Output is correct
15 Correct 895 ms 1456 KB Output is correct
16 Correct 1371 ms 2820 KB Output is correct
17 Correct 1164 ms 2904 KB Output is correct
18 Correct 51 ms 1636 KB Output is correct
19 Correct 1328 ms 2732 KB Output is correct
20 Correct 1093 ms 2648 KB Output is correct
21 Correct 946 ms 2692 KB Output is correct
22 Correct 718 ms 3400 KB Output is correct
23 Correct 658 ms 3108 KB Output is correct
24 Correct 830 ms 2564 KB Output is correct
25 Correct 726 ms 2476 KB Output is correct
26 Correct 1467 ms 3936 KB Output is correct
27 Correct 1986 ms 3912 KB Output is correct
28 Correct 1636 ms 4024 KB Output is correct
29 Correct 1188 ms 3832 KB Output is correct
30 Correct 1914 ms 3924 KB Output is correct
31 Correct 1949 ms 3916 KB Output is correct
32 Correct 1977 ms 3916 KB Output is correct
33 Correct 1617 ms 3876 KB Output is correct
34 Correct 1638 ms 3804 KB Output is correct
35 Correct 1632 ms 3784 KB Output is correct
36 Correct 1217 ms 3884 KB Output is correct
37 Correct 1225 ms 3916 KB Output is correct
38 Correct 1197 ms 3892 KB Output is correct
39 Correct 957 ms 4304 KB Output is correct
40 Correct 955 ms 4332 KB Output is correct
41 Correct 955 ms 4300 KB Output is correct
42 Correct 1026 ms 3508 KB Output is correct
43 Correct 1041 ms 3440 KB Output is correct
44 Correct 1048 ms 3396 KB Output is correct

Subtask #6
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 256 KB Output is correct
2 Correct 2 ms 252 KB Output is correct
3 Correct 40 ms 504 KB Output is correct
4 Correct 7 ms 632 KB Output is correct
5 Correct 17 ms 504 KB Output is correct
6 Correct 18 ms 504 KB Output is correct
7 Correct 20 ms 504 KB Output is correct
8 Correct 21 ms 504 KB Output is correct
9 Correct 22 ms 504 KB Output is correct
10 Correct 22 ms 504 KB Output is correct
11 Correct 22 ms 504 KB Output is correct
12 Correct 24 ms 504 KB Output is correct
13 Correct 29 ms 504 KB Output is correct
14 Correct 27 ms 504 KB Output is correct
15 Correct 24 ms 636 KB Output is correct
16 Correct 21 ms 504 KB Output is correct
17 Correct 21 ms 504 KB Output is correct
18 Correct 1480 ms 3876 KB Output is correct
19 Correct 1509 ms 3888 KB Output is correct
20 Correct 1507 ms 3992 KB Output is correct
21 Correct 1605 ms 3972 KB Output is correct
22 Correct 1599 ms 3976 KB Output is correct
23 Correct 2418 ms 4200 KB Output is correct
24 Correct 2561 ms 4076 KB Output is correct
25 Correct 2476 ms 4244 KB Output is correct
26 Correct 51 ms 1508 KB Output is correct
27 Correct 1318 ms 3968 KB Output is correct
28 Correct 1229 ms 4256 KB Output is correct
29 Correct 1228 ms 4420 KB Output is correct
30 Correct 1511 ms 3608 KB Output is correct
31 Correct 1179 ms 2804 KB Output is correct
32 Correct 895 ms 1456 KB Output is correct
33 Correct 1371 ms 2820 KB Output is correct
34 Correct 1164 ms 2904 KB Output is correct
35 Correct 51 ms 1636 KB Output is correct
36 Correct 1328 ms 2732 KB Output is correct
37 Correct 1093 ms 2648 KB Output is correct
38 Correct 946 ms 2692 KB Output is correct
39 Correct 718 ms 3400 KB Output is correct
40 Correct 658 ms 3108 KB Output is correct
41 Correct 830 ms 2564 KB Output is correct
42 Correct 726 ms 2476 KB Output is correct
43 Correct 1610 ms 7212 KB Output is correct
44 Correct 50 ms 1508 KB Output is correct
45 Correct 204 ms 5184 KB Output is correct
46 Correct 122 ms 5184 KB Output is correct
47 Correct 993 ms 7180 KB Output is correct
48 Correct 1589 ms 7164 KB Output is correct
49 Correct 973 ms 7264 KB Output is correct
50 Correct 827 ms 4400 KB Output is correct
51 Correct 851 ms 4356 KB Output is correct
52 Correct 826 ms 4472 KB Output is correct
53 Correct 1246 ms 6232 KB Output is correct
54 Correct 1215 ms 6368 KB Output is correct
55 Correct 1258 ms 6460 KB Output is correct
56 Correct 919 ms 7316 KB Output is correct
57 Correct 975 ms 7268 KB Output is correct
58 Correct 1624 ms 7212 KB Output is correct
59 Correct 1632 ms 7124 KB Output is correct
60 Correct 1642 ms 7148 KB Output is correct
61 Correct 1616 ms 7056 KB Output is correct
62 Correct 1389 ms 6784 KB Output is correct
63 Correct 1389 ms 6764 KB Output is correct
64 Correct 1589 ms 7128 KB Output is correct
65 Correct 957 ms 6612 KB Output is correct
66 Correct 1467 ms 3936 KB Output is correct
67 Correct 1986 ms 3912 KB Output is correct
68 Correct 1636 ms 4024 KB Output is correct
69 Correct 1188 ms 3832 KB Output is correct
70 Correct 1914 ms 3924 KB Output is correct
71 Correct 1949 ms 3916 KB Output is correct
72 Correct 1977 ms 3916 KB Output is correct
73 Correct 1617 ms 3876 KB Output is correct
74 Correct 1638 ms 3804 KB Output is correct
75 Correct 1632 ms 3784 KB Output is correct
76 Correct 1217 ms 3884 KB Output is correct
77 Correct 1225 ms 3916 KB Output is correct
78 Correct 1197 ms 3892 KB Output is correct
79 Correct 957 ms 4304 KB Output is correct
80 Correct 955 ms 4332 KB Output is correct
81 Correct 955 ms 4300 KB Output is correct
82 Correct 1026 ms 3508 KB Output is correct
83 Correct 1041 ms 3440 KB Output is correct
84 Correct 1048 ms 3396 KB Output is correct
85 Correct 2310 ms 6276 KB Output is correct
86 Correct 249 ms 5168 KB Output is correct
87 Correct 169 ms 5160 KB Output is correct
88 Correct 1617 ms 6448 KB Output is correct
89 Correct 2339 ms 6296 KB Output is correct
90 Correct 1617 ms 6364 KB Output is correct
91 Correct 1699 ms 3876 KB Output is correct
92 Correct 1699 ms 3836 KB Output is correct
93 Correct 2565 ms 4084 KB Output is correct
94 Correct 2047 ms 5528 KB Output is correct
95 Correct 2025 ms 5664 KB Output is correct
96 Correct 2305 ms 5524 KB Output is correct
97 Correct 1107 ms 7164 KB Output is correct
98 Correct 1464 ms 5816 KB Output is correct
99 Correct 2381 ms 6448 KB Output is correct
100 Correct 2350 ms 6332 KB Output is correct
101 Correct 2425 ms 6316 KB Output is correct
102 Correct 2361 ms 6280 KB Output is correct
103 Correct 2446 ms 5824 KB Output is correct
104 Correct 2468 ms 5892 KB Output is correct
105 Correct 1966 ms 5412 KB Output is correct
106 Correct 1644 ms 5012 KB Output is correct
107 Correct 1620 ms 6768 KB Output is correct
108 Correct 2468 ms 6260 KB Output is correct
109 Correct 1823 ms 5788 KB Output is correct