首页 > 代码库 > HYSBZ 1036 树的统计Count 树链剖分 线段树
HYSBZ 1036 树的统计Count 树链剖分 线段树
傻缺模板题,练手速和正确率用。。
#include <cstdio>#include <cstring>#include <algorithm>#include <map>#include <set>#include <bitset>#include <queue>#include <stack>#include <string>#include <iostream>#include <cmath>#include <climits>using namespace std;const int maxn = 3e4 + 10;int head[maxn], u[maxn << 1], v[maxn << 1], nxt[maxn << 1], ecnt;int siz[maxn], maxson[maxn], top[maxn], fa[maxn], tid[maxn], idcnt;int n, q, maxv[maxn << 2], sumv[maxn << 2], dep[maxn], sval[maxn], val[maxn];void adde(int uu, int vv) { u[ecnt] = uu; v[ecnt] = vv; nxt[ecnt] = head[uu]; head[uu] = ecnt++;}void init() { memset(head, -1, sizeof(head)); memset(maxson, -1, sizeof(maxson)); idcnt = ecnt = 0;}void dfs1(int now, int nowfa, int nowdep) { dep[now] = nowdep; fa[now] = nowfa; siz[now] = 1; for(int i = head[now]; ~i; i = nxt[i]) if(v[i] != nowfa) { dfs1(v[i], now, nowdep + 1); siz[now] += siz[v[i]]; if(maxson[now] == -1 || siz[maxson[now]] < siz[v[i]]) { maxson[now] = v[i]; } }}void dfs2(int now, int tp) { tid[now] = ++idcnt; top[now] = tp; if(maxson[now] == -1) return; dfs2(maxson[now], tp); for(int i = head[now]; ~i; i = nxt[i]) { if(v[i] != fa[now] && v[i] != maxson[now]) { dfs2(v[i], v[i]); } }}#define lson rt << 1, l, mid#define rson rt << 1 | 1, mid + 1, rvoid pushup(int rt) { int lc = rt << 1, rc = rt << 1 | 1; sumv[rt] = sumv[lc] + sumv[rc]; maxv[rt] = max(maxv[lc], maxv[rc]);}void build(int rt, int l, int r) { int mid = (l + r) >> 1; if(l == r) sumv[rt] = maxv[rt] = sval[l]; else { build(lson); build(rson); pushup(rt); }}void update(int rt, int l, int r, int pos, int Val) { if(l == r) maxv[rt] = sumv[rt] = Val; else { int mid = (l + r) >> 1; if(pos <= mid) update(lson, pos, Val); else update(rson, pos, Val); pushup(rt); }}int query_max(int rt, int l, int r, int ql, int qr) { if(ql <= l && qr >= r) return maxv[rt]; int mid = l + r >> 1, ret = -1e9; if(ql <= mid) ret = max(ret, query_max(lson, ql, qr)); if(qr > mid) ret = max(ret, query_max(rson, ql, qr)); return ret;}int query_sum(int rt, int l, int r, int ql, int qr) { if(ql <= l && qr >= r) return sumv[rt]; int mid = l + r >> 1, ret = 0; if(ql <= mid) ret += query_sum(lson, ql, qr); if(qr > mid) ret += query_sum(rson, ql, qr); return ret;}int ask_max(int x, int y) { int ret = -1e9; while(top[x] != top[y]) { if(dep[top[x]] < dep[top[y]]) { swap(x, y); } ret = max(ret, query_max(1, 1, idcnt, tid[top[x]], tid[x])); x = fa[top[x]]; } if(dep[x] > dep[y]) swap(x, y); ret = max(ret, query_max(1, 1, idcnt, tid[x], tid[y])); return ret;}int ask_sum(int x, int y) { int ret = 0; while(top[x] != top[y]) { if(dep[top[x]] < dep[top[y]]) swap(x, y); ret += query_sum(1, 1, idcnt, tid[top[x]], tid[x]); x = fa[top[x]]; } if(dep[x] > dep[y]) swap(x, y); ret += query_sum(1, 1, idcnt, tid[x], tid[y]); return ret;}int main() { while(scanf("%d", &n) != EOF) { init(); for(int i = 1; i < n; i++) { int a, b; scanf("%d%d", &a, &b); adde(a, b); adde(b, a); } for(int i = 1; i <= n; i++) scanf("%d", &val[i]); scanf("%d", &q); dfs1(1, 1, 1); dfs2(1, 1); for(int i = 1; i <= n; i++) { sval[tid[i]] = val[i]; } build(1, 1, idcnt); char cmd[16]; int a, b, c; while(q--) { scanf("%s%d%d", cmd, &a, &b); if(strcmp("QMAX", cmd) == 0) { printf("%d\n", ask_max(a, b)); } else if(strcmp("QSUM", cmd) == 0) { printf("%d\n", ask_sum(a, b)); } else { update(1, 1, idcnt, tid[a], b); } } } return 0;}
HYSBZ 1036 树的统计Count 树链剖分 线段树
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