oj.uz

Submission #24766

# Submission time Handle Problem Language Result Execution time Memory
24766 2017-06-13T10:40:15 Z Ushio Railway Trip (JOI17_railway_trip) C++14
20 / 100
 139 ms 115636 KB 
#include <bits/stdc++.h>
#define SZ(x) ((int) (x).size())
using namespace std;

class SegmentTree {
public:
    SegmentTree() = default;
    SegmentTree(const vector<int>& a):
        tree(vector<pair<int, int>>(4 * SZ(a) + 5)), n(SZ(a)) {
            build(0, 0, n - 1, a);
        }

    pair<int, int> query(int left, int right) const {
        pair<int, int> ret = query(0, 0, n - 1, left, right);
        ret.second = -ret.second;
        return ret;
    }
private:
    vector<pair<int, int>> tree;
    int n;

    void build(int node, int left, int right, const vector<int>& a) {
        if (left == right) {
            tree[node] = make_pair(a[left], -left);
        } else {
            int mid = (left + right) / 2;
            build(2 * node + 1, left, mid, a);
            build(2 * node + 2, mid + 1, right, a);
            tree[node] = max(tree[2 * node + 1], tree[2 * node + 2]);
        }
    }

    pair<int, int> query(int node, int left, int right, int lq, int rq) const {
        if (lq <= left && right <= rq) {
            return tree[node];
        } else {
            int mid = (left + right) / 2;
            pair<int, int> ret(-1, -1);
            if (lq <= mid) {
                ret = query(2 * node + 1, left, mid, lq, rq);
            }
            if (rq > mid) {
                ret = max(ret, query(2 * node + 2, mid + 1, right, lq, rq));
            }
            return ret;
        }
    }
};

vector<vector<int>> tree;
vector<int> indexToNode;
SegmentTree t;

const int LOG = 21;
array<vector<int>, LOG> anc;
array<vector<int>, LOG> ancCost;
vector<int> depth;
vector<int> posInParent;

int build(const vector<int>& a, int left, int right) {
    tree.push_back(vector<int>());
    int index = SZ(tree) - 1;
    if (left + 1 == right) {
        indexToNode[left] = index;
    } else {
        pair<int, int> imax = t.query(left + 1, right - 1);
        vector<int> poss = {left, imax.second};
        while (imax.second + 1 < right) {
            pair<int, int> cmax = t.query(imax.second + 1, right - 1);
            if (cmax.first != imax.first) {
                break;
            }
            poss.push_back(cmax.second);
            imax = cmax;
        }
        poss.push_back(right);
        for (int i = 0; i < SZ(poss) - 1; ++i) {
            int x = build(a, poss[i], poss[i + 1]);
            tree[index].push_back(x);
        }
    }
    return index;
}

void assignParent(int son, int parent, int costLeft, int costRight) {
    costLeft = min(costLeft, costRight + 1);
    costRight = min(costRight, costLeft + 1);
    if (costLeft == costRight + 1) {
        anc[0][son] = 3 * parent;
        ancCost[0][son] = costRight;
    } else if (costLeft == costRight) {
        anc[0][son] = 3 * parent + 1;
        ancCost[0][son] = costRight;
    } else {
        anc[0][son] = 3 * parent + 2;
        ancCost[0][son] = costLeft;
    }
}

void genDistTrees(int node) {
    for (int i = 0; i < SZ(tree[node]); ++i) {
        int to = tree[node][i];
        int costLeft = i;
        int costRight = SZ(tree[node]) - i - 1;
        posInParent[to] = i;
        depth[to] = depth[node] + 1;
        assignParent(3 * to, node, costLeft + 1, costRight);
        assignParent(3 * to + 1, node, costLeft, costRight);
        assignParent(3 * to + 2, node, costLeft, costRight + 1);
        genDistTrees(to);
    }
}

pair<int, int> ascend(int node, int height) {
    int cost = 0;
    for (int k = 0; k < LOG; ++k) {
        if (height & (1 << k)) {
            cost += ancCost[k][node];
            node = anc[k][node];
        }
    }
    return make_pair(node, cost);
}

int main() {
    #ifdef LOCAL_RUN
    freopen("task.in", "r", stdin);
    freopen("task.out", "w", stdout);
    //freopen("task.err", "w", stderr);
    #endif // ONLINE_JUDGE
    ios::sync_with_stdio(false);
    cin.tie(0);

    int n, k, q;
    cin >> n >> k >> q;

    vector<int> a(n);
    int rootCycle = true;
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
        if (i != 0 && i != n - 1 && a[i] == k) {
            rootCycle = false;
        }
    }
    t = SegmentTree(a);
    indexToNode = vector<int>(n);
    int root = build(a, 0, n - 1);
    for (int i = 0; i < LOG; ++i) {
        anc[i] = vector<int>(3 * SZ(tree));
        ancCost[i] = vector<int>(3 * SZ(tree));
    }
    for (int i = 0; i < 3; ++i) {
        anc[i][root + i] = root;
        ancCost[i][root + i] = 0;
    }
    depth = vector<int>(SZ(tree), 0);
    posInParent = vector<int>(SZ(tree), -1);
    genDistTrees(root);
    for (int k = 1; k < LOG; ++k) {
        for (int i = 0; i < SZ(anc[k]); ++i) {
            anc[k][i] = anc[k - 1][anc[k - 1][i]];
            ancCost[k][i] = ancCost[k - 1][i] + 
                ancCost[k - 1][anc[k - 1][i]];
        }
    }

    while (q-- > 0) {
        int a, b;
        cin >> a >> b;
        if (a + 1 == b) {
            cout << "0\n";
            continue;
        }
        a--; b--;
        if (a > b) {
            swap(a, b);
        }
        a = indexToNode[a] * 3 + 2;
        b = indexToNode[b - 1] * 3;
        int add = 0;
        if (depth[b / 3] > depth[a / 3]) {
            pair<int, int> c = ascend(b, depth[b / 3] - depth[a / 3]);
            b = c.first;
            add += c.second;
        } else if (depth[a / 3] > depth[b / 3]) {
            pair<int, int> c = ascend(a, depth[a / 3] - depth[b / 3]);
            a = c.first;
            add += c.second;
        }
        for (int k = LOG - 1; k >= 0; --k) {
            if (anc[k][a] / 3 != anc[k][b] / 3) {
                add += ancCost[k][a] + ancCost[k][b];
                a = anc[k][a];
                b = anc[k][b];
            }
        }
        int ans = add + posInParent[b / 3] - posInParent[a / 3] - 1
            + (a % 3 == 2) + (b % 3 == 0);
        if (anc[0][a] / 3 != root || rootCycle) {
            ans = min(ans, add + posInParent[a / 3] +
                    (SZ(tree[anc[0][a] / 3]) - posInParent[b / 3] - 1) +
                    (a % 3 == 0) + (b % 3 == 2) + 1);
        }
        cout << ans - 1 << '\n';
    }
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2332 KB Output is correct
2 Correct 0 ms 2332 KB Output is correct
3 Correct 0 ms 2332 KB Output is correct
4 Correct 0 ms 2332 KB Output is correct
5 Correct 0 ms 2200 KB Output is correct
6 Correct 0 ms 2200 KB Output is correct
7 Correct 0 ms 2200 KB Output is correct
8 Correct 0 ms 2200 KB Output is correct
9 Correct 0 ms 2200 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 3348 KB Output is correct
2 Correct 109 ms 99904 KB Output is correct
3 Correct 119 ms 105964 KB Output is correct
4 Correct 129 ms 110640 KB Output is correct
5 Correct 109 ms 112632 KB Output is correct
6 Correct 126 ms 115032 KB Output is correct
7 Correct 133 ms 115412 KB Output is correct
8 Correct 83 ms 59856 KB Output is correct
9 Correct 119 ms 90424 KB Output is correct
10 Correct 86 ms 76728 KB Output is correct
11 Correct 123 ms 88228 KB Output is correct
12 Correct 126 ms 88388 KB Output is correct
13 Correct 106 ms 88208 KB Output is correct
14 Correct 136 ms 88216 KB Output is correct
15 Correct 139 ms 88372 KB Output is correct
16 Correct 129 ms 88404 KB Output is correct
17 Correct 133 ms 115416 KB Output is correct
18 Correct 106 ms 115416 KB Output is correct
19 Correct 119 ms 115636 KB Output is correct

Subtask #3
0 / 25.0

# Verdict Execution time Memory Grader output
1 Runtime error 129 ms 103128 KB Execution killed because of forbidden syscall writev (20)
2 Halted 0 ms 0 KB -

Subtask #4
0 / 55.0

# Verdict Execution time Memory Grader output
1 Runtime error 126 ms 115412 KB Execution killed because of forbidden syscall writev (20)
2 Halted 0 ms 0 KB -