제출 #915456

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
915456		Julto	경주 (Race) (IOI11_race)	C++14	0 / 100	3 ms	14680 KiB

race

#include <bits/stdc++.h>
using namespace std;

const int mxN = 2e5 + 5, inf = 1e9;

int sz[mxN], cenPar[mxN], dep[mxN], par[mxN][18], sum[mxN];
vector<array<int, 2>> adj[mxN];
vector<array<int, 3>> dists[mxN];
bool done[mxN];

void dfs(int u, int p){
    par[u][0] = p;
    for(int i = 1; i < 18; i++){
        par[u][i] = par[par[u][i - 1]][i - 1];
    }
    for(auto i : adj[u]){
        if(i[0] == p) continue;
        dep[i[0]] = dep[u] + 1;
        sum[i[0]] = sum[u] + i[1];
        dfs(i[0], u);
    }
}

int lca(int a, int b){
    if(dep[a] < dep[b]){
        swap(a, b);
    }
    for(int i = 17; i >= 0; i--){
        if(dep[a] - (1 << i) >= dep[b]){
            a = par[a][i];
        }
    }
    if(a == b){
        return a;
    }
    for(int i = 17; i >= 0; i--){
        if(par[a][i] != par[b][i]){
            a = par[a][i];
            b = par[b][i];
        }
    }
    return par[a][0];
}

int calcDist(int a, int b){
    return sum[a] + sum[b] - 2 * sum[lca(a, b)];
}

int calcSz(int u, int p){
    sz[u] = 1;
    for(auto i : adj[u]){
        if(i[0] == p || done[i[0]]) continue;
        sz[u] += calcSz(i[0], u);
    }
    return sz[u];
}

int get(int u, int p, int x){
    for(auto i : adj[u]){
        if(i[0] == p || done[i[0]]) continue;
        if(sz[i[0]] * 2 > x){
            return get(i[0], u, x);
        }
    }
    return u;
}

int build(int u){
    int centroid = get(u, u, calcSz(u, u));
    done[centroid] = 1;
    dists[centroid].push_back({0, centroid, centroid});
    for(auto i : adj[centroid]){
        if(!done[i[0]]){
            int x = build(i[0]);
            cenPar[x] = centroid;
            for(auto j : dists[x]){
                dists[centroid].push_back({calcDist(centroid, j[2]), x, j[2]});
            }
        }
    }
    sort(dists[centroid].begin(), dists[centroid].end());
    return centroid;
}

int qry(int v, int k){
    int cur = v, subtree = v;
    int ans = inf;
    while(cur){
        int goal = k - calcDist(v, cur);
        array<int, 3> find = {goal, -inf, -inf};
        int lb = lower_bound(dists[cur].begin(), dists[cur].end(), find) - dists[cur].begin();
        for(int j = lb; j < dists[cur].size() && dists[cur][j][0] == goal; j++){
            if(dists[cur][j][1] == subtree) continue;
            int x = dep[v] + dep[cur] - 2 * dep[lca(cur, v)];
            int y = dep[dists[cur][lb][2]] + dep[cur] - 2 * dep[lca(dists[cur][lb][2], cur)];
            ans = min(ans, x + y);
        }
        cur = cenPar[cur];
    }
    return ans;
}

int best_path(int n, int k, int h[][2], int l[]){
    for(int i = 0; i < n - 1; i++){
        h[i][0]++, h[i][1]++;
        adj[h[i][0]].push_back({h[i][1], l[i]});
        adj[h[i][1]].push_back({h[i][0], l[i]});
    }
    dfs(1, 1);
    build(1);
    /*for(int i = 1; i <= n; i++){
        cout << i << '\n';
        for(auto j : dists[i]){
            cout << j[0] << " " << j[1] << " " << j[2] << "\n";
        }
        cout << '\n';
    }*/
    int ans = inf;
    for(int i = 1; i <= n; i++){
        ans = min(ans, qry(i, k));
    }

    return (ans == inf ? -1 : ans);
}

컴파일 시 표준 에러 (stderr) 메시지

race.cpp: In function 'int qry(int, int)':
race.cpp:92:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::array<int, 3> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |         for(int j = lb; j < dists[cur].size() && dists[cur][j][0] == goal; j++){
      |                         ~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57