@[_Revenge_](/user/750803) 字符串读入。
by XHY20180718 @ 2023-01-10 07:20:31
@[_Revenge_](/user/750803)
```cpp
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double db;
const int N = 4e5 + 50;
const int M = 1e5 + 50;
const int Mod = 1e9 + 7;
#define int long long
inline int read()
{
int x = 0, f = 1;
char ch = getchar();
while (ch < '0' || ch > '9')
{
if (ch == '-')
f = -1;
ch = getchar();
}
while (ch >= '0' && ch <= '9')
{
x = (x << 1) + (x << 3) + (ch ^ 48);
ch = getchar();
}
return x * f;
}
struct node
{
int to, nxt;
} e[N];
int head[N], cnt;
void add_edge(int u, int v)
{
++cnt;
e[cnt].to = v;
e[cnt].nxt = head[u];
head[u] = cnt;
}
int top[N], id[N], fa[N], son[N], siz[N], dep[N], res;
void dfs1(int u, int p)
{
dep[u] = dep[p] + 1;
siz[u] = 1;
fa[u] = p;
int maxn = -1;
for (int i = head[u]; i; i = e[i].nxt)
{
int v = e[i].to;
if (v == p)
continue;
dfs1(v, u);
siz[u] += siz[v];
if (siz[v] > maxn)
maxn = siz[v], son[u] = v;
}
}
void dfs2(int u, int topf)
{
top[u] = topf;
id[u] = ++res;
if (!son[u])
return;
dfs2(son[u], topf);
for (int i = head[u]; i; i = e[i].nxt)
{
int v = e[i].to;
if (v == fa[u] || v == son[u])
continue;
dfs2(v, v);
}
}
int n, m;
int tree[N], lazy[N];
int ls(int p) { return p << 1; }
int rs(int p) { return p << 1 | 1; }
void push_up(int p)
{
tree[p] = tree[ls(p)] + tree[rs(p)];
}
void change(int p, int l, int r, int k)
{
lazy[p] += k;
tree[p] += (r - l + 1) * k;
}
void push_down(int p, int l, int r)
{
int mid = l + r >> 1;
change(ls(p), l, mid, lazy[p]);
change(rs(p), mid + 1, r, lazy[p]);
lazy[p] = 0;
}
void update(int nx, int ny, int l, int r, int p, int k)
{
if (nx <= l && r <= ny)
{
change(p, l, r, k);
return;
}
push_down(p, l, r);
int mid = l + r >> 1;
if (nx <= mid)
update(nx, ny, l, mid, ls(p), k);
if (ny > mid)
update(nx, ny, mid + 1, r, rs(p), k);
push_up(p);
}
int query(int nx, int ny, int l, int r, int p)
{
int res = 0;
if (nx <= l && r <= ny)
return tree[p];
push_down(p, l, r);
int mid = l + r >> 1;
if (nx <= mid)
res += query(nx, ny, l, mid, ls(p));
if (ny > mid)
res += query(nx, ny, mid + 1, r, rs(p));
return res;
}
void update_range(int x, int y, int k)
{
while (top[x] != top[y])
{
if (dep[top[x]] < dep[top[y]])
swap(x, y);
update(id[top[x]], id[x], 1, n, 1, k);
x = fa[top[x]];
}
if (dep[x] > dep[y])
swap(x, y);
update(id[x], id[y], 1, n, 1, k);
}
int query_tree(int x)
{
return query(id[x], id[x] + siz[x] - 1, 1, n, 1);
}
signed main()
{
n = read();
for (int i = 1; i < n; ++i)
{
int u = read() + 1, v = read() + 1;
add_edge(u, v);
add_edge(v, u);
}
dfs1(1, 0);
dfs2(1, 1);
m = read();
while (m--)
{
char opt = getchar();
while(opt==' '||opt=='\n')opt=getchar();
int u, v, d;
if (opt == 'A')
{
u = read() + 1, v = read() + 1, d = read();
update_range(u, v, d);
}
else
{
u = read() + 1;
printf("%lld\n", query_tree(u));
}
}
return 0;
}
```
by XHY20180718 @ 2023-01-10 07:23:09
@[_Revenge_](/user/750803) getchar两次。第一次吃掉换行符，第二次才能读进op。
```cpp
getchar(); char op = getchar();
```
然后就过了。
by liangbowen @ 2023-01-10 08:09:51
@[liangbowen](/user/367488) 谢谢
by _Revenge_ @ 2023-01-10 10:14:56
@[xiehuiying](/user/399475) 谢谢
by _Revenge_ @ 2023-01-10 10:15:12