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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#563614 | #5148. Tree Distance | synonym | TL | 0ms | 16896kb | C++17 | 3.5kb | 2024-09-14 14:14:47 | 2024-09-14 14:14:48 |
Judging History
answer
#include "bits/stdc++.h"
using namespace std;
#define int long long
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()
const int mxn = 2e5+5;
int n;
vector<array<int,2>> adj[mxn];
//centroid
int vis[mxn];
vector<array<int,2>> dist[mxn];
int dfs_size(int v, int p) {
if (vis[v]) return 0;
int su = 1;
for (auto [u,d] : adj[v]) {
if (u==p) continue;
su += dfs_size(u,v);
}
return su;
}
void dfs_dist(int v, int p, int dt, int o) {
if (vis[v]) return;
dist[o].push_back({v,dt});
for (auto [u,d] : adj[v]) {
if (u==p) continue;
dfs_dist(u,v,dt+d,o);
}
}
int centroid(int v, int p, int sub) {
//check if v is valid
int ok = 1;
for (auto [u,d] : adj[v]) {
if (dfs_size(u,v)*2 > sub) {
ok=0;
break;
}
}
// cout<<v<<" "<<p<<" "<<sub<<endl;
if (!ok) {
for (auto [u,d] : adj[v]) {
// cout<<v<<" "<<u<<endl;
if (u==p) continue;
if (vis[u]) continue;
if (centroid(u,v,sub)) return 1;
}
// assert(0);
return 0;
} else {
dfs_dist(v,v,0,v);
vis[v] = 1;
for (auto [u,d] : adj[v]) {
if (vis[u]) continue;
int k = dfs_size(u,u);
centroid(u,u,k);
}
return 1;
}
}
struct RMQ {
int INF = 1e16;
int len = 1;
vector<int> segmx;
RMQ() {}
RMQ(int l) {
while (len < l) len *= 2;
segmx = vector<int>(2*len,INF);
}
RMQ(vector<int> arr) {
while (len < sz(arr)) len *= 2;
segmx = vector<int>(2*len,INF);
for (int i = 0; i < sz(arr); i++) {segmx[len+i] = arr[i];}
for (int i = len-1; i > 0; i--) {
segmx[i] = min(segmx[2*i], segmx[2*i+1]);
}
}
void set(int ind, int val) {
assert(0 <= ind && ind < len);
ind += len; segmx[ind] = val;
while (ind /= 2) {segmx[ind] = min(segmx[2*ind], segmx[2*ind+1]);}
}
int rangemin(int l, int r) {
int res = INF; r++;
for (l += len, r += len; l < r; l /= 2, r /= 2) {
if (l&1) res = min(res, segmx[l++]);
if (r&1) res = min(res, segmx[--r]);
}
return res;
}
};
vector<array<int,3>> rg;
int q;
array<int,3> qry[1000001];
RMQ rr;
int ans[mxn];
signed main() {
ios::sync_with_stdio(false); cin.tie(nullptr);
cin>>n;
for (int i=1; i<n; i++) {
int u,v,w; cin>>u>>v>>w; --u; --v;
adj[u].push_back({v,w});
adj[v].push_back({u,w});
}
centroid(0,0,n);
if (n==199999) return 0;
for (int X=0; X<n; X++) {
sort(all(dist[X]));
stack<array<int,2>> mono;
for (int i=0; i<sz(dist[X]); i++) {
while (sz(mono) && mono.top()[1] > dist[X][i][1]) {mono.pop();}
if (sz(mono)) {
rg.push_back({mono.top()[0],dist[X][i][0],mono.top()[1]+dist[X][i][1]});
}
mono.push(dist[X][i]);
}
while (sz(mono)) mono.pop();
for (int i=sz(dist[X])-1; i>=0; i--) {
while (sz(mono) && mono.top()[1] > dist[X][i][1]) {mono.pop();}
if (sz(mono)) {
rg.push_back({dist[X][i][0],mono.top()[0],mono.top()[1]+dist[X][i][1]});
}
mono.push(dist[X][i]);
}
}
if (n==199999) return 0;
rr = RMQ(n);
sort(all(rg)); reverse(all(rg));
cin>>q;
for (int i=0; i<q; i++) {
cin>>qry[i][0]>>qry[i][1]; --qry[i][0], --qry[i][1];
qry[i][2] = i;
}
sort(qry,qry+q);
reverse(qry,qry+q);
int rp = 0, qp = 0;
for (int i=n-1; i>=0; i--) {
while (rp < sz(rg) && rg[rp][0]==i) {
int pp = rg[rp][1];
int vv = rr.rangemin(pp,pp);
rr.set(pp,min(vv,rg[rp][2]));
rp++;
}
while (qp < q && qry[qp][0]==i) {
ans[qry[qp][2]] = rr.rangemin(i,qry[qp][1]);
qp++;
}
}
for (int i=0; i<q; i++) {
cout<<(ans[i]>1e15?-1:ans[i])<<"\n";
}
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 16896kb
input:
5 1 2 5 1 3 3 1 4 4 3 5 2 5 1 1 1 4 2 4 3 4 2 5
output:
-1 3 7 7 2
result:
ok 5 number(s): "-1 3 7 7 2"
Test #2:
score: -100
Time Limit Exceeded
input:
199999 31581 23211 322548833 176307 196803 690953895 34430 82902 340232856 36716 77480 466375266 7512 88480 197594480 95680 61864 679567992 19572 14126 599247796 188006 110716 817477802 160165 184035 722372640 23173 188594 490365246 54801 56250 304741654 10103 45884 643490340 127469 154479 214399361...