#include <iostream>
#include <vector>
#include <utility>
#include <algorithm>
using namespace std;
typedef long long ll;
typedef pair <int, ll> pil;
#define x first
#define y second
#define mp make_pair
int n, br, ss[100005], f[200005], tam[100005], tu[100005];
ll a[100005], gore[100005], dolje[100005];
vector <pil> ms[100005];
bool bio[100005], je[100005];
vector <ll> b;
void dfs1(int x, int p){
br++;
ss[x] = 1;
for(vector <pil>::iterator i = ms[x].begin() ; i != ms[x].end() ; ++i){
int o = (*i).x;
if(o == p || bio[o])
continue;
dfs1(o, x);
ss[x] += ss[o];
}
}
int dfs2(int x, int p){
for(vector <pil>::iterator i = ms[x].begin() ; i != ms[x].end() ; ++i){
int o = (*i).x;
if(o == p || bio[o])
continue;
if(ss[o] > br / 2)
return dfs2(o, x);
}
return x;
}
void update(int x, int y){
for(int i = x ; i <= 200001 ; i += (i & -i)){
f[i] += y;
}
}
ll sum(int x){
ll ret = 0;
for( ; x > 0 ; x -= (x & -x)){
ret += f[x];
}
return ret;
}
void initdp(int x, int p, ll sad, ll cur, ll maxi){
b.push_back(gore[x]);
b.push_back(dolje[x]);
for(vector <pil>::iterator i = ms[x].begin() ; i != ms[x].end() ; ++i){
pil o = *i;
if(o.x == p || bio[o.x])
continue;
dolje[o.x] = max(dolje[x], sad + o.y);
gore[o.x] = cur + a[o.x] - o.y;
je[o.x] = (gore[o.x] - maxi >= 0);
initdp(o.x, x, sad - a[x] + o.y, cur + a[o.x] - o.y, max(maxi, gore[o.x]));
}
}
void dfs3(int x, int p, int add){
update(tam[x], add);
for(vector <pil>::iterator i = ms[x].begin() ; i != ms[x].end() ; ++i){
int o = (*i).x;
if(o == p || bio[o])
continue;
dfs3(o, x, add);
}
}
ll dfs4(int x, int p, int cst){
ll ret = 0;
if(je[x]){
ret += sum(tu[x]);
}
for(vector <pil>::iterator i = ms[x].begin() ; i != ms[x].end() ; ++i){
pil o = *i;
if(o.x == p || bio[o.x])
continue;
ret += dfs4(o.x, x, o.y);
}
return ret;
}
void dfs5(int x, int p){
tam[x] = lower_bound(b.begin(), b.end(), dolje[x]) - b.begin() + 1;
tu[x] = lower_bound(b.begin(), b.end(), gore[x]) - b.begin() + 1;
for(vector <pil>::iterator i = ms[x].begin() ; i != ms[x].end() ; ++i){
int o = (*i).x;
if(o == p || bio[o])
continue;
dfs5(o, x);
}
}
ll sol;
void decompose(int root){
br = 0;
dfs1(root, -1);
int centroid = dfs2(root, -1);
bio[centroid] = 1;
gore[centroid] = 0;
dolje[centroid] = -a[centroid];
b.clear();
initdp(centroid, -1, -a[centroid], 0, 0);
sort(b.begin(), b.end());
b.resize(unique(b.begin(), b.end()) - b.begin());
dfs5(centroid, -1);
dfs3(centroid, -1, 1);
ll sad = sum(tu[centroid]) - 1;
for(vector <pil>::iterator i = ms[centroid].begin() ; i != ms[centroid].end() ; ++i){
pil o = *i;
if(bio[o.x])
continue;
dfs3(o.x, centroid, -1);
sad += dfs4(o.x, centroid, o.y);
//cout << "[" << dfs4(o.x, centroid, o.y) << "] ";
dfs3(o.x, centroid, 1);
}
//cout << endl;
dfs3(centroid, -1, -1);
sol += sad;
//cout << centroid << " : " << sad << endl;
for(vector <pil>::iterator i = ms[centroid].begin() ; i != ms[centroid].end() ; ++i){
int o = (*i).x;
if(bio[o])
continue;
decompose(o);
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n;
for(int i = 1 ; i <= n ; ++i){
cin >> a[i];
}
for(int i = 0 ; i < n - 1 ; ++i){
int x, y;
ll w;
cin >> x >> y >> w;
ms[x].push_back(mp(y, w));
ms[y].push_back(mp(x, w));
}
decompose(1);
cout << sol << endl;
return 0;
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
17 ms |
3328 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
27 ms |
3584 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
226 ms |
11084 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
329 ms |
14252 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
443 ms |
18348 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
222 ms |
6544 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
198 ms |
9032 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
452 ms |
11288 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
705 ms |
13688 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Incorrect |
979 ms |
16696 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |