paleta

input/code.cpp: In function 'int main()':
input/code.cpp:74:9: warning: statement has no effect [-Wunused-value]
     1==1;
         ^
input/code.cpp:83:18: warning: unused variable 'yk' [-Wunused-variable]
     int cyc = 0, yk;
                  ^

#include <bits/stdc++.h>

#define i64 long long
#define u64 unsigned long long
#define i32 int
#define u32 unsigned int

#define pii pair<int, int>
#define pll pair<long long, long long>

#define ld long double
#define defmod 1000000007

#define mati64(a,b) vector<vector<i64>>(a, vector<i64>(b, 0));
using namespace std;

i64 n, k;
int f[1010101];
int c[1010101];
int d1[1010101];
int t1[1010101];
int main(){
  cin.sync_with_stdio(0);
  cin.tie(0);
  
  
  cin >> n >> k;
  for(int i = 0; i < n; ++i){
    cin >> f[i+1];
    c[f[i+1]]++;
  }
  i64 ans = 1;
  int cn = 0;
  for(int i = 1; i <= n; ++i){
    if(c[i] || d1[i])
      continue;
    
    cn++;
    int cur = i;
    int ti = 1;
    int cyc = 0, yk;
    while(true){
      d1[cur] = cn;
      t1[cur] = ti;
      
      int ne = f[cur];
      if(d1[ne] && d1[ne] != cn){
        while(ti--)
	  ans = (ans*(k-1))%defmod;
	goto ohi;
	
      }
      else if(d1[ne]){
	cyc = t1[cur]-t1[ne]+1;
	yk = t1[ne]-1;
	break;
      }
      ti++;
      cur = ne;
    }
    while(yk--)
      ans = (ans*(k-1))%defmod;
    ans = (ans*k)%defmod;
    cyc--;
    if(cyc){
      ans = (ans*(k-1))%defmod;
      cyc--;
    }
    while(cyc > 0){
      ans = (ans*(k-2))%defmod;
      cyc--;
    }
    ohi:
    1==1;
  }
  for(int i = 1; i <= n; ++i){
    if(d1[i])
      continue;
    
    cn++;
    int cur = i;
    int ti = 1;
    int cyc = 0, yk;
    while(true){
      d1[cur] = cn;
      t1[cur] = ti;
      int ne = f[cur];
     
      if(d1[ne]){
	cyc = t1[cur]-t1[ne]+1;
	break;
      }
      ti++;
      cur = ne;
    }
    ans = (ans*k)%defmod;
    cyc--;
    if(cyc){
      ans = (ans*(k-1))%defmod;
      cyc--;
    }
    while(cyc > 0){
      ans = (ans*(k-2))%defmod;
      cyc--;
    }
  }
  cout << ans << endl;
  return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: ACCEPTED

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: WRONG ANSWER

Test 8

Verdict: WRONG ANSWER

Test 9

Verdict: ACCEPTED

Test 10

Verdict: WRONG ANSWER

Test 11

Verdict: ACCEPTED

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: ACCEPTED

Test 14

Verdict: WRONG ANSWER

Test 15

Verdict: WRONG ANSWER

Test 16

Verdict: WRONG ANSWER

Test 17

Verdict: WRONG ANSWER

Test 18

Verdict: WRONG ANSWER

Test 19

Verdict: ACCEPTED

Test 20

Verdict: WRONG ANSWER

Test 21

Verdict: ACCEPTED

Test 22

Verdict: WRONG ANSWER

Test 23

Verdict: WRONG ANSWER