Submission #38652

#	Time	Username	Problem	Language	Result	Execution time	Memory
38652		grumpy_gordon	Hard route (IZhO17_road)	C++14	0 / 100	16 ms	37348 KiB

road

/*
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#include <bits/stdc++.h>

//#pragma GCC optimize("O3")
//#pragma GCC optimize("Ofast,no-stack-protector")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx")
//#pragma GCC target("avx,tune=native")
//float __attribute__((aligned(32)))

using namespace std;

typedef long long ll;

typedef unsigned long long ull;

typedef long double ld;

int mysqrt(ll x){
    int l = 0, r = 1e9 + 1;
    while (r - l > 1){
        int m = (l + r) / 2;
        if (m * (ll)m <= x)
            l = m;
        else
            r = m;
    }
    return l;
}

mt19937 rnd(1337);

ll AR = 19, BR = 13, CR = 23, XR = 228, YR = 322, MODR = 1e9 + 993;

ll myrand(){
    ll ZR = (XR * AR + YR * BR + CR) % MODR;
    XR = YR;
    YR = ZR;
    return ZR;
}

const int Mod = 1e9 + 7;

int bpow(int x, int y){
    if (y == 0)
        return 1;
    if (y == 1)
        return x;
    int ret = bpow(x, y >> 1);
    ret = (ret * (ll)ret) % Mod;
    if (y & 1)
        ret = (ret * (ll)x) % Mod;
    return ret;
}

int bdiv(int x, int y){
    return (x * (ll)bpow(y, Mod - 2)) % Mod;
}

void setmin(int &x, int y){
    x = min(x, y);
}

void setmax(int &x, int y){
    x = max(x, y);
}

const ll llinf = 1e18 + 100;

const int maxn = 5e5 + 100, maxw = 1e6 + 100, inf = 2e9 + 100, sq = 300, mod = 1e9 + 7, LG = 17;

int n;

vector<int> e[maxn];

vector<int> q[maxn];

vector<int> g[maxn];

ll ans, answer = 1;

void upd(ll x, ll y){
    if (ans > x)
        return;
    if (ans < x)
        ans = x, answer = 0;
    answer += y;
}

int dfs0(int v, int par){
    int ret = 0;
    q[v].resize(e[v].size());
    g[v].resize(e[v].size());
    for (int i = 0; i < e[v].size(); i++)
    if (e[v][i] != par){
        q[v][i] = dfs0(e[v][i], v) + 1;
        ret = max(ret, q[v][i]);
    }
    return ret;
}

void dfs(int v, int par, int pv){
    int a = 0, b = 0, c = 0, x = 0, y = 0, z = 0;
    if (pv)
        a = pv, x = 1;
    for (int i = 0; i < e[v].size(); i++)
    if (e[v][i] != par){
        if (a < q[v][i])
            c = b, b = a, a = q[v][i], z = y, y = x, x = 1;
        else
        if (a == q[v][i])
            x++;
        else
        if (b < q[v][i])
            c = b, b = q[v][i], z = y, y = 1;
        else
        if (b == q[v][i])
            y++;
        else
        if (c < q[v][i])
            c = q[v][i], z = 1;
        else
        if (c == q[v][i])
            z++;
    }
    if (x + y + z > 2){
        if (x == 1)
            if (y == 1)
                upd(a * (ll)(b + c), z);
            else
                upd(a * (ll)2 * b, y * (ll)(y - 1) / 2);
        else
        if (x > 2)
            upd(a * (ll)2 * a, x * (ll)(x - 1) / 2);
        else
            upd(a * (ll)(a + b), x * (ll)y);
    }
    g[v][0] = q[v][0];
    for (int i = 1; i < q[v].size(); i++)
        g[v][i] = max(q[v][i], g[v][i - 1]);
    a = pv;
    for (int i = q[v].size() - 1; i >= 0; i--)
    if (e[v][i] != par){
        dfs(e[v][i], v, max(a, (i ? g[v][i - 1] : 0)) + 1);
        a = max(a, q[v][i]);
    }
}

int main()
{
    #ifdef ONPC
    //ifstream cin("a.in");
    //ofstream cout("a.out");
    freopen("a.in", "r", stdin);
    freopen("a.out", "w", stdout);
    #else
    //ifstream cin("road.in");
    //ofstream cout("road.out");
    //freopen("money.in", "r", stdin);
    //freopen("money.out", "w", stdout);
    #endif // ONPC
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cin >> n;
    if (n == 2){
        cout << "0 1";
        return 0;
    }
    for (int i = 1; i < n; i++){
        int v, u;
        cin >> v >> u;
        v--;
        u--;
        e[v].push_back(u);
        e[u].push_back(v);
    }
    int st;
    for (int i = 0; i < n; i++)
    if (e[i].size() > 1){
        st = i;
        break;
    }
    dfs0(st, -1);
    dfs(st, -1, 0);
    cout << ans << ' ' << answer;
}

Compilation message (stderr)

road.cpp: In function 'int dfs0(int, int)':
road.cpp:177:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < e[v].size(); i++)
                       ^
road.cpp: In function 'void dfs(int, int, int)':
road.cpp:189:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < e[v].size(); i++)
                       ^
road.cpp:222:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 1; i < q[v].size(); i++)
                       ^
road.cpp: In function 'int main()':
road.cpp:268:19: warning: 'st' may be used uninitialized in this function [-Wmaybe-uninitialized]
     dfs(st, -1, 0);
                   ^

• Subtask 1: 0 / 19
• Subtask 2: 0 / 33
• Subtask 3: 0 / 48