QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#182923#6737. Neighbourhooducup-team004#ML 0ms32912kbC++203.3kb2023-09-18 19:10:512023-09-18 19:10:51

Judging History

你现在查看的是最新测评结果

  • [2023-09-18 19:10:51]
  • 评测
  • 测评结果:ML
  • 用时:0ms
  • 内存:32912kb
  • [2023-09-18 19:10:51]
  • 提交

answer

#include <bits/stdc++.h>

using i64 = long long;

constexpr int N = 2E5;
constexpr int LogN = 20;

int n, q;
int x[N], y[N], w[N];
std::vector<int> adj[N];

int cdep[N], cpar[N], siz[N];
int par[LogN][N], in[LogN][N], out[LogN][N], seq[LogN][N];
int st[LogN][N];
i64 A[LogN][N], B[LogN][N];
bool vis[N];
int cur[LogN];
int blk[N + 1];

void dfs(int d, int x) {
    in[d][x] = cur[d]++;
    seq[d][in[d][x]] = x;
    siz[x] = 1;
    for (auto y : adj[x]) {
        if (y == par[d][x]) {
            continue;
        }
        par[d][y] = x;
        dfs(d, y);
        siz[x] += siz[y];
    }
    out[d][x] = cur[d];
}

int solve(int d, int r) {
    int t = cur[d];
    par[d][r] = -1;
    dfs(d, r);
    cdep[r] = d;
    vis[r] = true;
    for (auto y : adj[r]) {
        if (vis[y]) {
            continue;
        }
        y = solve(d + 1, y);
        cpar[y] = r;
    }
    return r;
}

int lca(int u, int v) {
    if (u == v) {
        return u;
    }
    u = in[0][u];
    v = in[0][v];
    if (u > v) {
        std::swap(u, v);
    }
    int k = std::__lg(v - u);
    int a = st[k][u];
    int b = st[k][v - (1 << k)];
    return in[0][a] < in[0][b] ? a : b;
}

i64 getdep(int u) {
    return A[0][in[0][u]];
}

i64 dist(int u, int v) {
    int l = lca(u, v);
    return getdep(u) + getdep(v) - 2 * getdep(l);
}

void modify(int i, int c) {
    int X = x[i], Y = y[i];
    int u = X, v = Y;
    while (cdep[u] > cdep[v]) {
        u = cpar[u];
    }
    while (cdep[v] > cdep[u]) {
        v = cpar[v];
    }
    while (u != v) {
        u = cpar[u];
        v = cpar[v];
    }
    while (u != -1) {
        int d = cdep[u];
        int l = std::max(in[d][X], in[d][Y]);
        int r = std::min(out[d][X], out[d][Y]);
        for (int j = l; j < r; j++) {
            A[d][j] += c;
        }
        u = cpar[u];
    }
}

int query(int x, i64 L) {
    int ans = 0;
    for (int i = 0; i < n; i++) {
        ans += dist(x, i) <= L;
    }
    return ans;
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    for (int i = 1; i <= N; i++) {
        blk[i] = std::sqrt(i);
    }
    
    std::cin >> n >> q;
    
    for (int i = 1; i < n; i++) {
        std::cin >> x[i] >> y[i] >> w[i];
        x[i]--, y[i]--;
        adj[x[i]].push_back(y[i]);
        adj[y[i]].push_back(x[i]);
    }
    cpar[solve(0, 0)] = -1;
    
    for (int i = 0; i < n; i++) {
        if (in[0][i] != 0) {
            st[0][in[0][i] - 1] = par[0][i];
        }
    }
    for (int k = 0; k + 1 < LogN; k++) {
        for (int i = 0; i + (2 << k) <= n - 1; i++) {
            int a = st[k][i];
            int b = st[k][i + (1 << k)];
            st[k + 1][i] = in[0][a] < in[0][b] ? a : b;
        }
    }
    
    for (int i = 1; i < n; i++) {
        modify(i, w[i]);
    }
    
    for (int _ = 0; _ < q; _++) {
        int o;
        std::cin >> o;
        
        if (o == 1) {
            int i, c;
            std::cin >> i >> c;
            modify(i, c - w[i]);
            w[i] = c;
        } else {
            int x;
            i64 d;
            std::cin >> x >> d;
            x--;
            std::cout << query(x, d) << "\n";
        }
    }
    
    return 0;
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 0ms
memory: 32912kb

input:

3 7
1 2 3
2 3 1
2 2 1
2 1 3
2 3 4
1 1 1
2 2 1
2 1 0
2 3 1

output:

2
2
3
3
1
2

result:

ok 6 numbers

Test #2:

score: -100
Memory Limit Exceeded

input:

200000 200000
1 2 146181238
2 3 45037818
3 4 176924060
4 5 969365276
5 6 683948619
6 7 356268194
7 8 871634797
8 9 630254480
9 10 283061123
10 11 204904965
11 12 838381393
12 13 516373812
13 14 253862710
14 15 223572474
15 16 114452997
16 17 145251056
17 18 905638436
18 19 375445402
19 20 549829545
...

output:


result: