#include <bits/stdc++.h>
using namespace std;
#ifdef ngu
#include "debug.h"
#else
#define debug(...) 42
#endif
const int N = 250005;
int shift(int i, int j, int n) {
i += j;
if (i < 1) {
i += n;
}
if (i > n) {
i -= n;
}
return i;
}
int valid(int n, int inputSeq[]) {
int delta = 0;
for (int i = 0; i < n; ++i) {
if (inputSeq[i] <= n) {
int j = inputSeq[i];
delta = j - i - 1;
break;
}
}
for (int i = 0; i < n; ++i) {
if (inputSeq[i] <= n) {
int j = shift(i + 1, delta, n);
if (j != inputSeq[i]) {
return 0;
}
}
}
return 1;
}
int pos[N];
int replacement(int n, int gondolaSeq[], int replacementSeq[]) {
memset(pos, -1, sizeof(pos));
for (int i = 0; i < n; ++i) {
pos[gondolaSeq[i]] = i;
}
set<int> cur;
for (int i = 0; i < n; ++i) {
cur.insert(i);
}
for (int i = 0; i < n; ++i) {
if (gondolaSeq[i] <= n) {
cur.erase(i);
}
}
int delta = 0;
for (int i = 0; i < n; ++i) {
if (gondolaSeq[i] <= n) {
int j = gondolaSeq[i];
delta = j - i - 1;
break;
}
}
for (int i = 0; i < n; ++i) {
gondolaSeq[i] = shift(i + 1, delta, n);
}
int m = -1;
for (int i = n + 1; i < N; ++i) {
if (!cur.size()) {
break;
}
int j = *cur.begin();
if (pos[i] != -1) {
j = pos[i];
cur.erase(j);
}
replacementSeq[++m] = gondolaSeq[j];
gondolaSeq[j] = i;
}
return m + 1;
}
const int MOD = (int) 1e9 + 9;
int countReplacement(int n, int inputSeq[]) {
if (valid(n, inputSeq) == 0) {
return 0;
}
memset(pos, -1, sizeof(pos));
for (int i = 0; i < n; ++i) {
pos[inputSeq[i]] = i;
}
int cnt = n;
for (int i = 0; i < n; ++i) {
if (inputSeq[i] <= n) {
cnt--;
}
}
int res = 1;
int delta = 0;
for (int i = 0; i < n; ++i) {
if (inputSeq[i] <= n) {
int j = inputSeq[i];
delta = j - i - 1;
break;
}
}
for (int i = 0; i < n; ++i) {
inputSeq[i] = shift(i + 1, delta, n);
}
if (n == 2 && cnt < 2) {
return 1;
}
for (int i = n + 1; i < N; ++i) {
if (!cnt) {
break;
}
if (pos[i] != -1) {
cnt--;
} else {
res = 1LL * res * cnt % MOD;
}
}
if (n == 2) {
res = 1LL * res * 2 % MOD;
}
return res;
}
Compilation message
/usr/bin/ld: /tmp/ccVsRPts.o: in function `main':
grader.cpp:(.text.startup+0xb6): undefined reference to `valid'
/usr/bin/ld: grader.cpp:(.text.startup+0x108): undefined reference to `countReplacement'
/usr/bin/ld: grader.cpp:(.text.startup+0x132): undefined reference to `replacement'
collect2: error: ld returned 1 exit status
