179 lines
4.8 KiB
C++
179 lines
4.8 KiB
C++
#include<cstdio>
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#include<cstring>
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#include<algorithm>
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using namespace std;
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#define MAXN 100005
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int anc[MAXN][17];
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int LL[MAXN][17][2], RR[MAXN][17][2];
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int ans[MAXN][17][2];
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int dep[MAXN];
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struct EDGE
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{
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EDGE() {}
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EDGE(int _to, int _next) { to = _to, next = _next; }
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int to, next;
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}edge[MAXN];
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int edgecnt, head[MAXN];
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void init()
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{
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memset(anc, -1, sizeof(anc));
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memset(head, -1, sizeof(head));
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edgecnt = 0;
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}
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void add(int s, int t)
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{
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edge[edgecnt] = EDGE(t, head[s]);
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head[s] = edgecnt++;
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}
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int val[MAXN];
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void dfs(int u, int fa, int deep)
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{
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anc[u][0] = fa;
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dep[u] = deep;
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if (val[u] < val[fa])
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{
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LL[u][0][0] = 2;
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LL[u][0][1] = 1;
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RR[u][0][0] = 2;
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RR[u][0][1] = 1;
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ans[u][0][0] = 2;
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ans[u][0][1] = 1;
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}
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else if (val[u]>val[fa])
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{
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LL[u][0][0] = 1;
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LL[u][0][1] = 2;
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RR[u][0][0] = 1;
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RR[u][0][1] = 2;
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ans[u][0][0] = 1;
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ans[u][0][1] = 2;
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}
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else
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{
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LL[u][0][0] = LL[u][0][1] = RR[u][0][0] = RR[u][0][1] = ans[u][0][0] = ans[u][0][1] = 1;
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}
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for (int i = head[u]; ~i; i = edge[i].next) dfs(edge[i].to, u, deep + 1);
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}
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void process(int n)
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{
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for (int j = 0; j < 16; j++)
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for (int i = 1; i <= n; i++)
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{
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if (dep[anc[i][j]]>(1 << j))
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{
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anc[i][j + 1] = anc[anc[i][j]][j];
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int A = anc[i][j];
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int len = (1 << j) + 1;
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if (LL[i][j][0] == len) LL[i][j + 1][0] = len - 1 + LL[A][j][0];
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else LL[i][j + 1][0] = LL[i][j][0];
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if (RR[A][j][0] == len) RR[i][j + 1][0] = len - 1 + RR[i][j][0];
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else RR[i][j + 1][0] = RR[A][j][0];
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if (LL[i][j][1] == len) LL[i][j + 1][1] = len - 1 + LL[A][j][1];
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else LL[i][j + 1][1] = LL[i][j][1];
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if (RR[A][j][1] == len) RR[i][j + 1][1] = len - 1 + RR[i][j][1];
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else RR[i][j + 1][1] = RR[A][j][1];
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ans[i][j + 1][0] = max(ans[i][j][0], ans[A][j][0]);
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ans[i][j + 1][0] = max(ans[i][j + 1][0], RR[i][j][0] + LL[A][j][0] - 1);
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ans[i][j + 1][1] = max(ans[i][j][1], ans[A][j][1]);
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ans[i][j + 1][1] = max(ans[i][j + 1][1], RR[i][j][1] + LL[A][j][1] - 1);
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}
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}
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}
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int lca(int u, int v)
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{
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if (dep[u] < dep[v]) swap(u, v);
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for (int i = 16; i >= 0; i--) if (dep[u] - (1 << i) >= dep[v]) u = anc[u][i];
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if (u == v) return u;
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for (int i = 16; i >= 0; i--)
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if (anc[u][i] != anc[v][i])
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{
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u = anc[u][i];
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v = anc[v][i];
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}
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return anc[u][0];
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}
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int getans(int u, int v)
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{
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int l = lca(u, v);
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int Ru = 1, ansu = 1;
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bool first = 1;
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for (int i = 16; i >= 0; i--)
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if (dep[u] - (1 << i) >= dep[l])
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{
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if (first)
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{
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Ru = RR[u][i][0];
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ansu = ans[u][i][0];
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first = 0;
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u = anc[u][i];
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continue;
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}
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ansu = max(ansu, ans[u][i][0]);
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ansu = max(ansu, Ru + LL[u][i][0] - 1);
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int len = (1 << i) + 1;
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if (len == RR[u][i][0]) Ru += RR[u][i][0] - 1;
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else Ru = RR[u][i][0];
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u = anc[u][i];
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}
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int Rv = 1, ansv = 1;
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first = 1;
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for (int i = 16; i >= 0; i--)
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if (dep[v] - (1 << i) >= dep[l])
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{
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if (first)
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{
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Rv = RR[v][i][1];
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ansv = ans[v][i][1];
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first = 0;
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v = anc[v][i];
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continue;
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}
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ansv = max(ansv, ans[v][i][1]);
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ansv = max(ansv, Rv + LL[v][i][1] - 1);
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int len = (1 << i) + 1;
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if (len == RR[v][i][1]) Rv += RR[v][i][1] - 1;
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else Rv = RR[v][i][1];
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v = anc[v][i];
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}
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int ans = max(ansu, ansv);
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ans = max(ans, Ru + Rv - 1);
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return ans;
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}
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int main()
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{
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int T;
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int ks = 0;
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scanf("%d", &T);
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bool ok = 0;
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while (T--)
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{
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if (ok != 0)
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{
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puts("");
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}
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ok = 1;
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printf("Case #%d:\n", ++ks);
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int n;
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scanf("%d", &n);
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init();
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for (int i = 1; i <= n; i++) scanf("%d", &val[i]);
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for (int i = 2; i <= n; i++)
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{
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int s;
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scanf("%d", &s);
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add(s, i);
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}
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dfs(1, -1, 1);
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process(n);
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int Q;
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scanf("%d", &Q);
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while (Q--)
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{
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int u, v;
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scanf("%d %d", &u, &v);
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printf("%d\n", getans(u, v));
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}
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}
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return 0;
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}
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