Codeforces 1140G Double Tree 倍增 + dp

#include<bits/stdc++.h>
#define LL long long
#define fi first
#define se second
#define mk make_pair
#define PLL pair<LL, LL>
#define PLI pair<LL, int>
#define PII pair<int, int>
#define SZ(x) ((int)x.size())
#define ull unsigned long long

using namespace std;

const int N = 3e5 + 7;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1000000007;
const double eps = 1e-13;
const double PI = acos(-1);

int n, q, depth[N];
LL d[N], gg[N], dp[N][2][2][20];
int f[N][20];
vector<pair<int, PLL>> G[N];
vector<PLI> E[N];

void dfs(int u, int fa, PLL dis) {
    depth[u] = depth[fa] + 1;
    if(u > 1) {
        f[u][0] = fa;
        dp[u][0][0][0] = min(dis.fi, dis.se + d[u] + d[fa]);
        dp[u][1][1][0] = min(dis.se, dis.fi + d[u] + d[fa]);
        dp[u][0][1][0] = min(dis.fi + d[fa], dis.se + d[u]);
        dp[u][1][0][0] = min(dis.se + d[fa], dis.fi + d[u]);
        for(int i = 1; i < 20; i++) f[u][i] = f[f[u][i - 1]][i - 1];
        for(int i = 1; i < 20; i++) {
            int v = f[u][i - 1];
            dp[u][0][0][i] = min(dp[u][0][0][i - 1] + dp[v][0][0][i - 1], dp[u][0][1][i - 1] + dp[v][1][0][i - 1]);
            dp[u][1][1][i] = min(dp[u][1][1][i - 1] + dp[v][1][1][i - 1], dp[u][1][0][i - 1] + dp[v][0][1][i - 1]);
            dp[u][0][1][i] = min(dp[u][0][0][i - 1] + dp[v][0][1][i - 1], dp[u][0][1][i - 1] + dp[v][1][1][i - 1]);
            dp[u][1][0][i] = min(dp[u][1][1][i - 1] + dp[v][1][0][i - 1], dp[u][1][0][i - 1] + dp[v][0][0][i - 1]);
        }
    }
    for(auto& e : G[u]) {
        if(e.fi == fa) continue;
        dfs(e.fi, u, e.se);
    }
}

int getLca(int u, int v) {
    if(depth[u] < depth[v]) swap(u, v);
    for(int i = 19; i >= 0; i--)
        if(depth[f[u][i]] >= depth[v]) u = f[u][i];
    if(u == v) return u;
    for(int i = 19; i >= 0; i--)
        if(f[u][i] != f[v][i]) u = f[u][i], v = f[v][i];
    return f[u][0];
}

PLL calc(int u, int op1, int v) {
    int dis = depth[u] - depth[v];
    LL g[2], tmp[2];
    g[op1] = 0;
    g[op1 ^ 1] = d[u];
    for(int i = 19; i >= 0; i--) {
        if(dis >> i & 1) {
            tmp[0] = g[0], tmp[1] = g[1];
            g[0] = min(tmp[0] + dp[u][0][0][i], tmp[1] + dp[u][1][0][i]);
            g[1] = min(tmp[1] + dp[u][1][1][i], tmp[0] + dp[u][0][1][i]);
            u = f[u][i];
        }
    }
    return mk(g[0], g[1]);
}

int main() {
    scanf("%d", &n);
    for(int i = 1; i <= n; i++) scanf("%lld", &d[i]);
    for(int i = 2; i <= n; i++) {
        int u, v; LL w1, w2;
        scanf("%d%d%lld%lld", &u, &v, &w1, &w2);
        G[u].push_back(mk(v, mk(w1, w2)));
        G[v].push_back(mk(u, mk(w1, w2)));
        E[u].push_back(mk(w1 + w2, v));
        E[v].push_back(mk(w1 + w2, u));
    }
    priority_queue<PLI, vector<PLI>, greater<PLI> > que;
    for(int i = 1; i <= n; i++) {
        gg[i] = d[i];
        que.push(mk(d[i], i));
    }
    while(!que.empty()) {
        int u = que.top().se;
        LL val = que.top().fi;
        que.pop();
        if(val > gg[u]) continue;
        for(auto& e : E[u]) {
            if(gg[e.se] > val + e.fi) {
                gg[e.se] = val + e.fi;
                que.push(mk(gg[e.se], e.se));
            }
        }
    }
    for(int i = 1; i <= n; i++) d[i] = gg[i];
    dfs(1, 0, mk(0, 0));
    scanf("%d", &q);
    while(q--) {
        int u, v;
        scanf("%d%d", &u, &v);
        int op1 = (u & 1) ? 0 : 1;
        int op2 = (v & 1) ? 0 : 1;
        if(u & 1) u = (u + 1) >> 1;
        else u >>= 1;
        if(v & 1) v = (v + 1) >> 1;
        else v >>= 1;
        int Lca = getLca(u, v);
        PLL disu = calc(u, op1, Lca);
        PLL disv = calc(v, op2, Lca);
        printf("%lld\n", min(disu.fi + disv.fi, disu.se + disv.se));
    }
    return 0;
}

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