제출 #991106

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
991106		borisAngelov	Traffic (IOI10_traffic)	C++17	50 / 100	1065 ms	262144 KiB

traffic

#include "traffic.h"
#include <bits/stdc++.h>

using namespace std;

const int maxn = 1000005;
const long long inf = (1LL << 62);

int n;
int a[maxn];

vector<int> g[maxn];

struct SegmentTree
{
    long long tree[4 * maxn];
    long long lazy[4 * maxn];

    void pushLazy(int node, int l, int r)
    {
        tree[node] += lazy[node];

        if (l != r)
        {
            lazy[2 * node] += lazy[node];
            lazy[2 * node + 1] += lazy[node];
        }

        lazy[node] = 0;
    }

    void update(int node, int l, int r, int ql, int qr, long long delta)
    {
        pushLazy(node, l, r);

        if (l > qr || r < ql)
        {
            return;
        }

        if (ql <= l && r <= qr)
        {
            lazy[node] += delta;
            pushLazy(node, l, r);
            return;
        }

        int mid = (l + r) / 2;

        update(2 * node, l, mid, ql, qr, delta);
        update(2 * node + 1, mid + 1, r, ql, qr, delta);

        tree[node] = max(tree[2 * node], tree[2 * node + 1]);
    }

    long long query(int node, int l, int r, int ql, int qr)
    {
        pushLazy(node, l, r);

        if (l > qr || r < ql)
        {
            return -inf;
        }

        if (ql <= l && r <= qr)
        {
            return tree[node];
        }

        int mid = (l + r) / 2;

        return max(query(2 * node, l, mid, ql, qr), query(2 * node + 1, mid + 1, r, ql, qr));
    }
};

SegmentTree tree;

long long subtreeSum[maxn];
long long ans[maxn];

void dfsInit(int node, int par)
{
    subtreeSum[node] = a[node];

    for (int i = 0; i < g[node].size(); ++i)
    {
        if (g[node][i] != par)
        {
            dfsInit(g[node][i], node);
            subtreeSum[node] += subtreeSum[g[node][i]];
        }
    }

    tree.update(1, 1, n, node, node, subtreeSum[node]);
}

void dfsSolve(int node, int par)
{
    if (1 < node && node < n)
    {
        ans[node] = max(tree.query(1, 1, n, 1, node - 1), tree.query(1, 1, n, node + 1, n));
    }
    else if (node == 1)
    {
        ans[node] = tree.query(1, 1, n, 2, n);
    }
    else
    {
        ans[node] = tree.query(1, 1, n, 1, n - 1);
    }

    for (int i = 0; i < g[node].size(); ++i)
    {
        int to = g[node][i];

        if (to != par)
        {
            subtreeSum[node] -= subtreeSum[to];
            tree.update(1, 1, n, node, node, -subtreeSum[to]);
            subtreeSum[to] += subtreeSum[node];
            tree.update(1, 1, n, to, to, +subtreeSum[node]);

            dfsSolve(to, node);

            tree.update(1, 1, n, to, to, -subtreeSum[node]);
            subtreeSum[to] -= subtreeSum[node];
            tree.update(1, 1, n, node, node, +subtreeSum[to]);
            subtreeSum[node] += subtreeSum[to];
        }
    }
}

int LocateCentre(int N, int pp[], int S[], int D[])
{
    n = N;

    for (int i = 1; i <= n; ++i)
    {
        a[i] = pp[i - 1];
    }

    for (int i = 1; i <= n - 1; ++i)
    {
        int x = S[i - 1];
        int y = D[i - 1];

        ++x;
        ++y;

        g[x].push_back(y);
        g[y].push_back(x);
    }

    dfsInit(1, -1);
    dfsSolve(1, -1);

    long long big = inf;
    int node = -1;

    for (int i = 1; i <= n; ++i)
    {
        //cout << i << " :: " << ans[i] << endl;

        if (big > ans[i])
        {
            big = ans[i];
            node = i;
        }
    }

    //cout << big << endl;

    return node - 1;
}

컴파일 시 표준 에러 (stderr) 메시지

traffic.cpp: In function 'void dfsInit(int, int)':
traffic.cpp:85:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |     for (int i = 0; i < g[node].size(); ++i)
      |                     ~~^~~~~~~~~~~~~~~~
traffic.cpp: In function 'void dfsSolve(int, int)':
traffic.cpp:112:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  112 |     for (int i = 0; i < g[node].size(); ++i)
      |                     ~~^~~~~~~~~~~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 0 / 25
• Subtask 3: 25 / 25
• Subtask 4: 0 / 25