传送门
分析
不想翻译了。。
这道题跟牛客多校那道题很类似,但是因为做法不同就导致了这两个题的做法完全不同了
我们去离线处理每一个询问,找到这个询问能往上走的最高点,然后在树状数组对应的位置打上标记,然后向下
d
f
s
dfs
dfs即可
代码
#pragma GCC optimize(3)
#include <bits/stdc++.h>
#define debug(x) cout<<#x<<":"<<x<<endl;
#define dl(x) printf("%lld\n",x);
#define di(x) printf("%d\n",x);
#define _CRT_SECURE_NO_WARNINGS
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> PII;
typedef vector<int> VI;
const int INF = 0x3f3f3f3f;
const int N = 2e5 + 10,M = N * 2;
const ll mod = 1000000007;
const double eps = 1e-9;
const double PI = acos(-1);
template<typename T>inline void read(T &a) {
char c = getchar(); T x = 0, f = 1; while (!isdigit(c)) {if (c == '-')f = -1; c = getchar();}
while (isdigit(c)) {x = (x << 1) + (x << 3) + c - '0'; c = getchar();} a = f * x;
}
int gcd(int a, int b) {return (b > 0) ? gcd(b, a % b) : a;}
int n,a[N],m;
int tr[N];
int fa[N][25], mx[N][25];
int h[N],e[M],ne[M],idx;
VI query[N];
int ans[N];
int lowbit(int x){
return x & -x;
}
void ad(int x,int y){
ne[idx] = h[x],e[idx] = y,h[x] = idx++;
}
void add(int x,int c){
for(int i = x;i < N;i += lowbit(i)) tr[i] += c;
}
int sum(int x){
int res = 0;
for(int i = x;i;i -= lowbit(i)) res += tr[i];
return res;
}
int ans_up(int x, int k) {
for (int i = 20; i >= 0; i--) {
if (fa[x][i] && mx[x][i] <= k) x = fa[x][i];
}
return x;
}
void dfs(int u, int f) {
fa[u][0] = f;
if (u != 1) mx[u][0] = a[f];
else mx[u][0] = INF;
for (int k = 1; k <= 20; k++) {
fa[u][k] = fa[fa[u][k - 1]][k - 1];
mx[u][k] = max(mx[u][k - 1], mx[fa[u][k - 1]][k - 1]);
}
for (int i = h[u]; ~i; i = ne[i]) {
int j = e[i];
if (j == f) continue;
dfs(j, u);
}
}
void dfs_(int u,int f){
for(int p:query[u]) add(p,1);
ans[u] = sum(a[u]);
for(int i = h[u];~i;i = ne[i]){
int j = e[i];
if(j == f) continue;
dfs_(j,u);
}
for(int p:query[u]) add(p,-1);
}
int main() {
memset(h,-1,sizeof h);
read(n),read(m);
for(int i = 1;i <= n;i++){
int x,y;
read(x),read(y);
if(i == 1){
ad(1,0);
a[1] = x;
}
else{
ad(y,i);
a[i] = x;
}
}
dfs(1,0);
for(int i = 1;i <= m;i++){
int x,y,z;
read(x),read(y),read(z);
x = ans_up(x,z);
query[x].pb(y);
}
dfs_(1,0);
for(int i = 1;i <= n;i++) printf("%d ",ans[i]);
return 0;
}