| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 592938 | Bobaa | Min-max tree (BOI18_minmaxtree) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9 + 7;
const int maxn = 7e4 + 5;
int n;
struct query {
int x, y, z;
char scanf() {
static char in[10];
scanf("%s %d %d %d", in, &x, &y, &z);
return *in;
}
};
vector<int> edge[maxn];
vector<query> qs[256];
int par[maxn][17];
int nxt[maxn];
int dep[maxn];
void dfs(int x, int p) {
par[x][0] = p;
dep[x] = dep[p] + 1;
for (int i = 1; i < 17; i++) par[x][i] = par[par[x][i - 1]][i - 1];
for (int i : edge[x]) {
if (i == p) continue;
dfs(i, x);
}
}
int lca(int x, int y) {
if (dep[x] < dep[y]) swap(x, y);
for (int i = 17; i--; ) if ((dep[x] - dep[y]) >> i) x = par[x][i];
if (x == y) return x;
for (int i = 17; i--; ) if (par[x][i] != par[y][i]) {
x = par[x][i];
y = par[y][i];
}
return par[x][0];
}
int mn[maxn];
int mx[maxn];
int paint(int c[], int s, int e, int x) {
if (dep[s] <= dep[e]) return s;
if (c[s]) return nxt[s] = paint(c, nxt[s], e, x);
c[s] = x;
return nxt[s] = paint(c, par[s][0], e, x);
}
int find(vector<int> &v, int x) {
return lower_bound(v.begin(), v.end(), x) - v.begin();
}
struct matching {
vector<int> edge[maxn];
int rev[maxn];
int vis[maxn];
int lv[maxn];
int n;
void bfs() {
queue<int> q;
for (int i = 2; i <= n; i++) {
if (vis[i]) lv[i] = inf;
else {
lv[i] = 0;
q.push(i);
}
}
while (!q.empty()) {
int x = q.front();
q.pop();
for (int i : edge[x]) if (rev[i]) {
if (lv[rev[i]] < inf) continue;
lv[rev[i]] = lv[x] + 1;
q.push(rev[i]);
}
}
}
int dfs(int x) {
for (int i : edge[x]) if (rev[i] == 0 || lv[rev[i]] == lv[x] + 1 && dfs(rev[i])) {
vis[x] = 1;
rev[i] = x;
return 1;
}
return 0;
}
int process(int N) {
n = N;
int ret = 0;
while (1) {
bfs();
int res = 0;
for (int i = 2; i <= n; i++) {
if (vis[i]) continue;
res += dfs(i);
}
if (res == 0) break;
ret += res;
}
return ret;
}
} mt;
int main() {
scanf("%d", &n);
for (int i = 1, a, b; i < n; i++) {
scanf("%d %d", &a, &b);
edge[a].push_back(b);
edge[b].push_back(a);
}
dfs(1, 0);
int k;
scanf("%d", &k);
vector<int> cp;
for (int i = 0; i < k; i++) {
query q;
char c = q.scan();
qs[c].push_back(q);
cp.push_back(q.z);
}
cp.push_back(0);
sort(cp.begin(), cp.end());
cp.erase(unique(cp.begin(), cp.end()), cp.end());
sort(qs['m'].begin(), qs['m'].end(), [&](const query &x, const query &y) {
return x.z > y.z;
});
sort(qs['M'].begin(), qs['M'].end(), [&](const query &x, const query &y) {
return x.z < y.z;
});
for (query i : qs['m']) {
int p = lca(i.x, i.y);
paint(mn, i.x, p, i.z);
paint(mn, i.y, p, i.z);
}
for (query i : qs['M']) {
int p = lca(i.x, i.y);
paint(mx, i.x, p, i.z);
paint(mx, i.y, p, i.z);
}
for (int i = 2; i <= n; i++) {
if (mn[i]) mt.edge[i].push_back(find(cp, mn[i]));
if (mn[i] == mx[i]) continue;
if (mx[i]) mt.edge[i].push_back(find(cp, mx[i]));
}
mt.process(n);
for (int i = 1; i < cp.size(); i++) mn[mt.rev[i]] = cp[i];
for (int i = 2; i <= n; i++) printf("%d %d %d\n", i, par[i][0], mn[i]);
return 0;
}