BZOJ4756: [Usaco2017 Jan]Promotion Counting(線段樹合並)
阿新 • • 發佈：2019-02-18
.com space lower clu return bzoj const bits motion
題意
題目鏈接
Sol
線段樹合並板子題
#include<bits/stdc++.h> using namespace std; const int MAXN = 400000, SS = MAXN * 21; inline int read() { char c = getchar(); int x = 0, f = 1; while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();} while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar(); return x * f; } int N, p[MAXN], fa[MAXN], root[MAXN], tot, ans[MAXN]; vector<int> v[MAXN]; int ls[SS], rs[SS], sum[SS]; void insert(int &k, int l, int r, int p, int v) { if(!k) k = ++tot; sum[k]++; if(l == r) return ; int mid = l + r >> 1; if(p <= mid) insert(ls[k], l, mid, p, v); else insert(rs[k], mid + 1, r, p, v); } int Query(int k, int l, int r, int ql, int qr) { if(ql <= l && r <= qr) return sum[k]; int mid = l + r >> 1; if(ql > mid) return Query(rs[k], mid + 1, r, ql, qr); else if(qr <= mid) return Query(ls[k], l, mid, ql, qr); else return Query(ls[k], l, mid, ql, qr) + Query(rs[k], mid + 1, r, ql, qr); } int Merge(int x, int y) { if(!x || !y) return x ^ y; ls[x] = Merge(ls[x], ls[y]); rs[x] = Merge(rs[x], rs[y]); sum[x] += sum[y]; return x; } void dfs(int x) { for(int i = 0; i < v[x].size(); i++) { int to = v[x][i]; dfs(to); root[x] = Merge(root[x], root[to]); } ans[x] = Query(root[x], 1, N, p[x] + 1, N); insert(root[x], 1, N, p[x], 1); } void Des() { static int date[MAXN], num = 0; for(int i = 1; i <= N; i++) date[++num] = p[i]; sort(date + 1, date + num + 1); num = unique(date + 1, date + num + 1) - date - 1; for(int i = 1; i <= N; i++) p[i] = lower_bound(date + 1, date + N + 1, p[i]) - date; } int main() { N = read(); for(int i = 1; i <= N; i++) p[i] = read(); Des(); for(int i = 2; i <= N; i++) fa[i] = read(), v[fa[i]].push_back(i); dfs(1); for(int i = 1; i <= N; i++) printf("%d\n", ans[i]); return 0; } /* */
BZOJ4756: [Usaco2017 Jan]Promotion Counting(線段樹合並)