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  • [洛谷P3178] [HAOI2015]树上操作

    题目链接:###

    点我

    题目分析:###

    和树链剖分模板没什么区别,子树加就是直接在线段树上(modify(1, num[u], num[u] + siz[u] - 1, d))即可(用dfs序的思想,且注意减掉(u)节点自己)
    不多讲了,直接上代码吧。

    代码:###

    #include<bits/stdc++.h>
    #define int long long
    #define N (100000 + 5)
    using namespace std;
    inline int read() {
    	int cnt = 0, f = 1; char c = getchar();
    	while (!isdigit(c)) {if (c == '-') f = -f; c = getchar();}
    	while (isdigit(c)) {cnt = (cnt << 3) + (cnt << 1) + c - '0'; c = getchar();}
    	return cnt * f;
    }
    int first[N], nxt[N * 2], to[N * 2], tot;
    void Add(int x, int y) {
    	nxt[++tot] = first[x];
    	first[x] = tot;
    	to[tot] = y;
    }
    int father[N], son[N], num[N], top[N], id[N], siz[N], dep[N], idx;
    void dfs1(int cur, int fa) {
    	father[cur] = fa, siz[cur] = 1, dep[cur] = dep[fa] + 1;
    	for (register int i = first[cur]; i; i = nxt[i]) {
    		int v = to[i];
    		if (v != fa) {
    			dfs1(v, cur);
    			siz[cur] += siz[v];
    			if (siz[son[cur]] < siz[v]) son[cur] = v; 
    		}
    	}
    }
    void dfs2(int cur, int tp) {
    	num[cur] = ++idx, id[idx] = cur, top[cur] = tp;	
    	if (son[cur]) dfs2(son[cur], tp);
    	for (register int i = first[cur]; i; i = nxt[i]) {
    		int v = to[i];
    		if (!num[v]) dfs2(v, v);
    	}
    }
    struct node {
    	int l, r, sum, tag;
    	#define l(p) tree[p].l
    	#define r(p) tree[p].r
    	#define sum(p) tree[p].sum
    	#define tag(p) tree[p].tag
    }tree[N << 2];
    void push_up(int p) {
    	sum(p) = sum(p << 1) + sum(p << 1 | 1);
    }
    void push_down(int p) {
    	sum(p << 1) += tag(p) * (r(p << 1) - l(p << 1) + 1);
    	sum(p << 1 | 1) += tag(p) * (r(p << 1 | 1) - l(p << 1 | 1) + 1);
    	tag(p << 1) += tag(p), tag(p << 1 | 1) += tag(p);
    	tag(p) = 0; 
    }
    int a[N];
    void build_tree(int p, int l, int r) {
    	l(p) = l, r(p) = r;
    	if (l == r) {sum(p) = a[id[l]]; return;}
    	int mid = (l + r) >> 1;
    	build_tree(p << 1, l, mid);
    	build_tree(p << 1 | 1, mid + 1, r);
    	push_up(p);
    }
    void modify(int p, int l, int r, int d) {
    	if (l <= l(p) && r >= r(p)) {
    		sum(p) += d * (r(p) - l(p) + 1), tag(p) += d;
    		return;
    	}
    	push_down(p);
    	int mid = (l(p) + r(p)) >> 1;
    	if (l <= mid) modify(p << 1, l, r, d);
    	if (r > mid) modify(p << 1 | 1, l, r, d);
    	push_up(p); 
    }
    int query(int p, int l, int r) {
    	if (l <= l(p) && r >= r(p)) return sum(p);
    	push_down(p);
    	int mid = (l(p) + r(p)) >> 1;
    	long long val = 0;
    	if (l <= mid) val += query(p << 1, l, r);
    	if (r > mid) val += query(p << 1 | 1, l, r);
    	return val;
    }
    int chain_query(int u, int v) {
    	long long ans = 0;
    	while (top[u] != top[v]) {
    		if (dep[top[u]] < dep[top[v]]) swap(u, v);
    		ans += query(1, num[top[u]], num[u]);
    		u = father[top[u]];
    	}
    	if (dep[u] < dep[v]) swap(u, v);
    	ans += query(1, num[v], num[u]);
    	return ans;
    }
    int n, m, x, y;
    int ope;
    void solve() {
    	n = read(); m = read();
    	for (register int i = 1; i <= n; i++) a[i] = read();
    	for (register int i = 1; i < n; i++) {
    		x = read(), y = read();
    		Add(x, y), Add(y, x);
    	}
    	dfs1(1, 0); dfs2(1, 1); build_tree(1, 1, n);
    	for (register int i = 1; i <= m; i++) {
    		ope = read();
    		if (ope == 1) {
    			x = read(); y = read();
    			modify(1, num[x], num[x], y);
    		}
    		if (ope == 2) {
    			x = read(); y = read();
    			modify(1, num[x], num[x] + siz[x] - 1, y);
    		}
    		if (ope == 3) {
    			x = read();
    			printf("%lld
    ", chain_query(1, x));
    		}
    	}
    }
    signed main() {
    	solve();
    	return 0; 
    }
    
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  • 原文地址:https://www.cnblogs.com/kma093/p/11141195.html
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