Submission #68605673

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,n) for (int i=(a);i<(n);i++)
#define per(i,a,n) for (int i=(n)-1;i>=(a);i--)
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
typedef vector<int> VI;
typedef basic_string<int> BI;
typedef long long ll;
typedef pair<int,int> PII;
typedef double db;
mt19937 mrand(random_device{}()); 
const ll mod=1000000007;
int rnd(int x) { return mrand() % x;}
ll powmod(ll a,ll b) {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head

const int N=5100;
int dp[N][N];
int n,k,p[N],vis[N],ans;
VI cc[N];
int solve(VI a) {
	int m=SZ(a);
	rep(i,0,m) rep(j,0,m) dp[i][j]=0;
	rep(i,0,m) a[i]%=n;
	rep(i,0,m) cc[a[i]].pb(i);
	rep(len,0,m) rep(j,0,m) {
		int i=(j+m-len)%m;
		if (len==0) {
			dp[j][i]=0;
			continue;
		}
		dp[j][i]=dp[(j+m-1)%m][i];
		if (i<j) {
			for (auto c:cc[a[j]]) {
				if (c>=i&&c<j)
					dp[j][i]=max(dp[j][i],dp[c][i]+dp[j][c==m-1?0:c+1]+1);
			}
		} else {
			for (auto c:cc[a[j]]) {
				if (c<j||c>=i)
					dp[j][i]=max(dp[j][i],dp[c][i]+dp[j][c==m-1?0:c+1]+1);
			}			
		}
	}
	int ans=0;
	rep(i,0,m) rep(j,i+1,m) if (a[i]==a[j]) ans=max(ans,1+dp[(j+m-1)%m][i]
		+dp[(i+m-1)%m][j]);
	rep(i,0,m) cc[a[i]].clear();
	return ans;
}
int main() {
	scanf("%d%d",&n,&k);
	rep(i,1,n*k+1) scanf("%d",&p[i]);
	rep(i,1,n*k+1) if (!vis[i]) {
		VI pat;
		int u=i;
		while (!vis[u]) {
			pat.pb(u);
			vis[u]=1;
			u=p[u];
		}
		ans+=solve(pat);
	}
	printf("%d\n",ans);
}

Submission Info

Compile Error

Main.cpp: In function ‘int main()’:
Main.cpp:59:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   59 |         scanf("%d%d",&n,&k);
      |         ~~~~~^~~~~~~~~~~~~~
Main.cpp:60:29: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   60 |         rep(i,1,n*k+1) scanf("%d",&p[i]);
      |                        ~~~~~^~~~~~~~~~~~

Judge Result