/* WHAT IS EXTRA INFORAMZTION GTR RR */
#include <stdio.h>
#include <stdlib.h>
int max(int i, int j) { return i > j ? i : j; }
/*
* For "Q" queries, use LCA + prefix sum on tree ~ 3O(lgn) [for finding lca and almost-lca]
*
* Every B queries of any type, do naive dp on tree (reverse edge order)
* to find answer for "C" queries ~ O(n)
*
* On "C" queries, use cached answer from above and count all edges that appeared after that (by "Q")
* ~ O(B lgn)
*
*
* Time complexity = O(N^2 / B) + O(N lgn) + O(N B lgn)
*
* Let B = sqrt(N / lgN)
*/
#define N 120001
#define B 300
int n, q, pp[N], jj[N], dd[N], up[N], temp, inc[N];
void pus_(int **eh, int *eo, int i, int j) {
int o = eo[i]++;
if (0 == o) eh[i] = (int*)malloc(2 * sizeof **eh);
else if (0 == (o & o - 1)) eh[i] = (int*)realloc(eh[i], 2 * o * sizeof **eh);
eh[i][o] = j;
}
int *eh[N], *fh[N], eo[N];
void link(int u, int v, int w) {
pus_(eh, eo, u, v);
--eo[u];
pus_(fh, eo, u, w);
pus_(eh, eo, v, u);
--eo[v];
pus_(fh, eo, v, w);
}
void dfs(int u, int p) {
inc[u] = (up[u] > up[p]) + inc[p];
for (int j = 0; j < eo[u]; ++j) if (eh[u][j] != p) {
int v = eh[u][j];
dd[v] = dd[u] + 1;
pp[v] = u;
jj[v] = (dd[u] - dd[jj[u]] == dd[jj[u]] - dd[jj[jj[u]]]) ? jj[jj[u]]: u;
up[v] = fh[u][j];
dfs(v, u);
}
}
int lca(int u, int v) {
while (dd[u] != dd[v]) {
if (dd[u] < dd[v]) temp = u, u = v, v = temp;
u = (dd[jj[u]] >= dd[v]) ? jj[u] : pp[u];
}
while (u != v)
if (jj[u] != jj[v]) u = jj[u], v = jj[v];
else u = pp[u], v = pp[v];
return u;
}
int anc(int u, int dep) {
while (dd[u] > dep)
u = (dd[jj[u]] >= dep) ? jj[u] : pp[u];
return u;
}
struct Query {
char type[2];
int a, b;
} qq[N * 2];
/* u = data node, v = ask node */
int query_yesno(int u, int v, int time) {
if (u == v) return 1;
int a = lca(u, v);
int va, ua;
ua = anc(u, dd[a] + 1);
va = anc(v, dd[a] + 1);
if (u == a) {
return inc[v] - inc[va] == dd[v] - dd[va] && up[v] <= time;
}
if (v == a) {
return inc[u] - inc[ua] == 0 && up[ua] <= time;
}
return (dd[v] - dd[va] == inc[v] - inc[va]) && (inc[u] - inc[ua] == 0)
&& up[va] > up[ua] && up[v] <= time;
}
int dp[N], comp[N];
void efs(int u, int time, int root) {
comp[u] = root;
for (int j = 0; j < eo[u]; ++j)
if (fh[u][j] <= time && comp[eh[u][j]] == -1)
efs(eh[u][j], time, root);
}
void build(int ii, int tme) {
for (int i = 1; i <= n; ++i)
dp[i] = 1, comp[i] = -1;
for (int i = ii; i >= 0; --i) {
if (qq[i].type[0] != 'S')
continue;
int x = dp[qq[i].a], y = dp[qq[i].b];
dp[qq[i].a] = max(y + 1, dp[qq[i].a]);
dp[qq[i].b] = max(x + 1, dp[qq[i].b])
}
for (int i = 1; i <= n; ++i)
if (comp[i] == -1)
efs(i, tme, i);
}
int counted[N];
int main() {
scanf("%d%d", &n, &q);
q = n + q - 1;
for (int j = 0, i = 0; i < q; ++i) {
int a, b = 0;
char *s = qq[i].type;
scanf(" %s%d", s, &a);
if (s[0] == 'S') {
scanf("%d", &b);
link(a, b, j++);
} else if (s[0] == 'Q')
scanf("%d", &b);
qq[i].a = a, qq[i].b = b;
}
up[1] = 1e9;
pp[1] = jj[1] = 1;
dfs(1, 1);
build(-1, -1);
int at = 0;
for (int j = 0, i = 0; i < q; ++i) {
if (qq[i].type[0] == 'S')
++j;
if (i % B == 0) {
build(i, j);
at = i + 1;
}
if (qq[i].type[0] == 'Q')
puts(query_yesno(qq[i].b, qq[i].a, j - 1) ? "yes": "no");
else if (qq[i].type[0] == 'C') {
build(i, j);
printf("%d\n", dp[qq[i].a]);
continue;
int focus = qq[i].a;
int addition = 0;
for (int k = at; k < i; ++k)
if (qq[k].type[0] == 'S') {
int a = qq[k].a, b = qq[k].b;
if (counted[a] != i + 1 &&
comp[a] != comp[focus] && query_yesno(focus, a, j - 1))
++addition, counted[a] = i + 1;
if (counted[b] != i + 1 &&
comp[b] != comp[focus] && query_yesno(focus, b, j - 1))
++addition, counted[b] = i + 1;
}
printf("%d\n", dp[focus] + addition);
}
}
}
Compilation message
servers.c: In function 'pus_':
servers.c:30:26: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
30 | else if (0 == (o & o - 1)) eh[i] = (int*)realloc(eh[i], 2 * o * sizeof **eh);
| ~~^~~
servers.c: In function 'build':
servers.c:117:46: error: expected ';' before '}' token
117 | dp[qq[i].b] = max(x + 1, dp[qq[i].b])
| ^
| ;
118 | }
| ~
servers.c: In function 'main':
servers.c:128:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
128 | scanf("%d%d", &n, &q);
| ^~~~~~~~~~~~~~~~~~~~~
servers.c:135:9: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
135 | scanf(" %s%d", s, &a);
| ^~~~~~~~~~~~~~~~~~~~~
servers.c:137:13: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
137 | scanf("%d", &b);
| ^~~~~~~~~~~~~~~
servers.c:140:13: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
140 | scanf("%d", &b);
| ^~~~~~~~~~~~~~~
