#include <bits/stdc++.h>
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
using namespace std;
typedef long long ll;
typedef unsigned long long llu;
typedef pair<int, int> pii;
typedef pair<int, pii> piii;
typedef pair<ll, ll> pll;
typedef pair<ll, int> pli;
typedef pair<int, ll> pil;
typedef pair<string, int> psi;
typedef pair<char, int> pci;
typedef pair<int, char> pic;
const long double PI = 3.141592653589793238462643383279502884197;
int n;
const int B = 128;
const ll pr[2] = { 1000000009, 1000000021 };
ll rhq[50002][2];
vector<int> v[50002];
int rotn[50002];
char visit[50002];
char s[50002];
int flag, len;
int cent(int o, int pa, int cap) {
for (int i : v[o])
if (i != pa && !visit[i] && rotn[i] > cap)
return cent(i, o, cap);
return o;
}
int pre(int o, int pa) {
int ret = 1;
for (int i : v[o])
if (i != pa && !visit[i])
ret += pre(i, o);
return rotn[o] = ret;
}
unordered_map<ll, int> um;
deque<char> dq;
void pcal(int o, int pa, int di, int h1, int h2) {
h1 = (h1 + rhq[di][0] * s[o]) % pr[0];
h2 = (h2 + rhq[di][1] * s[o]) % pr[1]; // 경로 길이 반환..
int ha = h1 * rhq[n - di][0] % pr[0]; // 끝의 높이를 n에 맞춰줌
int hb = h2 * rhq[n - di][1] % pr[1];
um[ha * pr[1] + hb]++;
if (di < len) {
for (int i : v[o])
if (i != pa && !visit[i])
pcal(i, o, di + 1, h1, h2);
}
}
void mcal(int o, int pa, int di, int h1, int h2) {
h1 = (h1 + rhq[di][0] * s[o]) % pr[0];
h2 = (h2 + rhq[di][1] * s[o]) % pr[1];
int ha = h1 * rhq[n - di][0] % pr[0];
int hb = h2 * rhq[n - di][1] % pr[1];
um[ha * pr[1] + hb]--;
if (di < len) {
for (int i : v[o])
if (i != pa && !visit[i])
mcal(i, o, di + 1, h1, h2);
}
}
int root;
void cal(int o, int pa, int di, int dd, int h1, int h2, int r1, int r2, int s1, int s2) {
h1 = (h1 + rhq[di][0] * s[o]) % pr[0];
h2 = (h2 + rhq[di][1] * s[o]) % pr[1];
dq.push_back(s[o]);
int ha, hb, sa, sb;
vector<char> rev;
while (dd == 0 || ((di - dd + 1) * 2 + dd > len) && dd <= di) {
char w = dq.front();
dq.pop_front();
rev.push_back(w);
r1 = (r1 + rhq[n - dd][0] * w) % pr[0];
r2 = (r2 + rhq[n - dd][1] * w) % pr[1];
s1 = (s1 + rhq[dd][0] * w) % pr[0];
s2 = (s2 + rhq[dd][1] * w) % pr[1];
dd++;
}
sa = s1 * rhq[n - (dd - 1)][0] % pr[0];
sb = s2 * rhq[n - (dd - 1)][1] % pr[1];
ha = (h1 - s1 + pr[0]) % pr[0];
hb = (h2 - s2 + pr[1]) % pr[1];
ha = ha * rhq[n - di][0] % pr[0];
hb = hb * rhq[n - di][1] % pr[1];
auto t = um.find(ha * pr[1] + hb);
// printf("%d %d : %d %d %d %d %d\n", root, o, len, di, dd, r1 == sa, r2 == sb);
if (((di - dd + 1) * 2 + dd == len) && r1 == sa && r2 == sb && t != um.end() && t->second > 0)
flag = 1;
if (di < len) {
for (int i : v[o])
if (i != pa && !visit[i]) {
if (o == pa) mcal(i, o, 1, 0, 0);
cal(i, o, di + 1, dd, h1, h2, r1, r2, s1, s2);
if (o == pa) pcal(i, o, 1, 0, 0);
}
}
while (!rev.empty()) {
dq.push_front(rev.back());
rev.pop_back();
}
dq.pop_back();
}
void go(int o) {
pre(o, o);
int t = cent(o, o, rotn[o] / 2);
visit[t]++;
root = t;
for (int i : v[t])
if (!visit[i])
pcal(i, t, 1, 0, 0);
um[0] = 50001;
cal(t, t, 0, 0, 0, 0, 0, 0, 0, 0);
dq.clear();
um.clear();
for (int i : v[t])
if (!visit[i])
go(i);
visit[t]--;
}
int main() {
scanf("%d", &n);
scanf("%s", s);
rhq[0][0] = rhq[0][1] = 1;
for (int i = 1; i <= n; i++)
for (int j = 0; j < 2; j++)
rhq[i][j] = rhq[i - 1][j] * B % pr[j];
for (int i = 0; i < n - 1; i++) {
int a, b;
scanf("%d %d", &a, &b);
a--; b--;
v[a].push_back(b);
v[b].push_back(a);
}
int l = 0, r = (n - 1) / 2, mid;
int ans = 0;
while (l <= r) {
mid = (l + r) / 2;
flag = 0, len = mid * 2 + 1;
go(0);
if (flag) l = mid + 1;
else r = mid - 1;
}
ans = max(ans, l * 2 + 1);
l = 1, r = n / 2;
while (l <= r) {
mid = (l + r) / 2;
flag = 0, len = mid * 2;
go(0);
if (flag) l = mid + 1;
else r = mid - 1;
}
ans = max(ans, l * 2);
printf("%d", ans - 2);
}
Compilation message
lampice.cpp: In function 'void cal(int, int, int, int, int, int, int, int, int, int)':
lampice.cpp:87:54: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
while (dd == 0 || ((di - dd + 1) * 2 + dd > len) && dd <= di) {
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~
lampice.cpp: In function 'int main()':
lampice.cpp:155:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &n);
~~~~~^~~~~~~~~~
lampice.cpp:156:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%s", s);
~~~~~^~~~~~~~~
lampice.cpp:165:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &a, &b);
~~~~~^~~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
12 ms |
1528 KB |
Output is correct |
| 2 |
Correct |
27 ms |
1528 KB |
Output is correct |
| 3 |
Correct |
78 ms |
1656 KB |
Output is correct |
| 4 |
Correct |
106 ms |
1656 KB |
Output is correct |
| 5 |
Correct |
6 ms |
1528 KB |
Output is correct |
| 6 |
Correct |
5 ms |
1528 KB |
Output is correct |
| 7 |
Correct |
5 ms |
1400 KB |
Output is correct |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
5035 ms |
9640 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
5065 ms |
7720 KB |
Time limit exceeded |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
12 ms |
1528 KB |
Output is correct |
| 2 |
Correct |
27 ms |
1528 KB |
Output is correct |
| 3 |
Correct |
78 ms |
1656 KB |
Output is correct |
| 4 |
Correct |
106 ms |
1656 KB |
Output is correct |
| 5 |
Correct |
6 ms |
1528 KB |
Output is correct |
| 6 |
Correct |
5 ms |
1528 KB |
Output is correct |
| 7 |
Correct |
5 ms |
1400 KB |
Output is correct |
| 8 |
Execution timed out |
5035 ms |
9640 KB |
Time limit exceeded |
| 9 |
Halted |
0 ms |
0 KB |
- |
