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Submission #47525

# Submission time Handle Problem Language Result Execution time Memory
47525 2018-05-05T02:26:17 Z aome Special graph (IZhO13_specialg) C++17
100 / 100
 133 ms 34904 KB 
#include <bits/stdc++.h>
using namespace std;

struct Query {
    int t, x, y;
    Query (int t, int x, int y) : t(t), x(x), y(y) {}
};

const int N = 100005;

int n, m, cnt;
int h[N], p[20][N], nxt[N];
int par[N], deg[N], res[N];
int pos[N], cir[N], sz[N];
bool visit[N], iscir[N];
vector<int> G[N];
vector<Query> query;

void dfs(int u) {
    for (auto v : G[u]) {
        if (v == p[0][u]) continue;
        h[v] = h[u] + 1, dfs(v);
    }
}

void find_cir(int u) {
    pos[u] = ++sz[cnt], cir[u] = cnt;
    if (cir[nxt[u]]) return;
    find_cir(nxt[u]);
}

void pre() {
    for (int i = 1; i <= n; ++i) {
        if (nxt[i]) deg[nxt[i]]++;
    }

    queue<int> qu;
    for (int i = 1; i <= n; ++i) {
        if (!deg[i]) qu.push(i);
    }

    while (qu.size()) {
        int u = qu.front(); qu.pop();
        if (nxt[u]) {
            deg[nxt[u]]--;
            if (!deg[nxt[u]]) {
                qu.push(nxt[u]);
            }
        }
    }

    for (int i = 1; i <= n; ++i) {
        if (nxt[i] && !deg[i]) {
            p[0][i] = nxt[i], G[nxt[i]].push_back(i);
        }
    }

    for (int i = 1; i <= n; ++i) {
        if (!p[0][i]) p[0][i] = i, dfs(i);
    }

    for (int i = 1; i <= 17; ++i) {
        for (int j = 1; j <= n; ++j) {
            p[i][j] = p[i - 1][p[i - 1][j]];
        }
    }

    for (int i = 1; i <= n; ++i) {
        if (deg[i] && !cir[i]) ++cnt, find_cir(i);
    }
}

bool check(int u, int v) {
    for (int i = 17; i >= 0; --i) {
        if (h[p[i][u]] >= h[v]) u = p[i][u];
    }
    return u == v;
}

int find(int u) {
    return u == par[u] ? u : par[u] = find(par[u]);
}

void join(int u, int v) {
    u = find(u), v = find(v);
    if (u == v) { iscir[u] = 1; return; }
    par[u] = v;
}

int main() {
//    freopen("in.txt", "r", stdin);
//    freopen("out.txt", "w", stdout);
    ios::sync_with_stdio(false);
    cin >> n;
    for (int i = 1; i <= n; ++i) cin >> nxt[i];
    for (int i = 1; i <= n; ++i) par[i] = i;
    pre();

    cin >> m;
    for (int i = 1; i <= m; ++i) {
        int t, x, y;
        cin >> t; x = y = 0;
        if (t == 1) cin >> x, visit[x] = 1;
        else cin >> x >> y;
        query.push_back(Query(t, x, y));
    }

    for (int i = 1; i <= n; ++i) {
        if (!visit[i] && nxt[i]) join(i, nxt[i]);
    }

    for (int i = m - 1; i >= 0; --i) {
        int t = query[i].t, x = query[i].x, y = query[i].y;
        if (t == 1) join(x, nxt[x]);
        else {
            int px = find(x), py = find(y);
            if (px == py) {
                if (check(x, y)) res[i] = h[x] - h[y];
                else {
                    int tmp = p[17][x];
                    if (!cir[tmp] || !cir[px] || cir[tmp] != cir[y]) res[i] = -1;
                    else {
                        res[i] = h[x] + pos[y] - pos[tmp];
                        if (iscir[px]) {
                            if (pos[tmp] > pos[y]) res[i] += sz[cir[y]];
                        }
                        else {
                            if (pos[tmp] < pos[y]) {
                                if (pos[tmp] <= pos[px] && pos[px] < pos[y]) res[i] = -1;
                            }
                            else {
                                if (pos[tmp] <= pos[px] || pos[px] < pos[y]) res[i] = -1;
                                else res[i] += sz[cir[y]];
                            }
                        }
                    }
                }
            }
            else res[i] = -1;
        }
    }

    for (int i = 0; i < m; ++i) {
        if (query[i].t == 2) cout << res[i] << '\n';
    }
}

Subtask #1
100.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 3196 KB Output is correct
2 Correct 6 ms 3360 KB Output is correct
3 Correct 6 ms 3440 KB Output is correct
4 Correct 8 ms 3760 KB Output is correct
5 Correct 6 ms 3760 KB Output is correct
6 Correct 15 ms 4276 KB Output is correct
7 Correct 16 ms 4620 KB Output is correct
8 Correct 16 ms 4924 KB Output is correct
9 Correct 17 ms 5140 KB Output is correct
10 Correct 13 ms 5432 KB Output is correct
11 Correct 116 ms 17996 KB Output is correct
12 Correct 103 ms 17996 KB Output is correct
13 Correct 133 ms 21168 KB Output is correct
14 Correct 88 ms 21168 KB Output is correct
15 Correct 92 ms 22676 KB Output is correct
16 Correct 98 ms 24180 KB Output is correct
17 Correct 119 ms 30528 KB Output is correct
18 Correct 120 ms 32684 KB Output is correct
19 Correct 112 ms 34720 KB Output is correct
20 Correct 107 ms 34904 KB Output is correct