Submission #25003186

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define fill0(a) memset(a,0,sizeof(a))
#define fill1(a) memset(a,-1,sizeof(a))
#define fillbig(a) memset(a,63,sizeof(a))
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define eprintf(...) fprintf(stderr,__VA_ARGS__)
template<typename T1,typename T2> void chkmin(T1 &x,T2 y){if(x>y) x=y;}
template<typename T1,typename T2> void chkmax(T1 &x,T2 y){if(x<y) x=y;}
typedef pair<int,int> pii;
typedef long long ll;
typedef unsigned int u32;
typedef unsigned long long u64;
typedef long double ld;
namespace fastio{
	#define FILE_SIZE 1<<23
	char rbuf[FILE_SIZE],*p1=rbuf,*p2=rbuf,wbuf[FILE_SIZE],*p3=wbuf;
	inline char getc(){return p1==p2&&(p2=(p1=rbuf)+fread(rbuf,1,FILE_SIZE,stdin),p1==p2)?-1:*p1++;}
	inline void putc(char x){(*p3++=x);}
	template<typename T> void read(T &x){
		x=0;char c=getchar();T neg=0;
		while(!isdigit(c)) neg|=!(c^'-'),c=getchar();
		while(isdigit(c)) x=(x<<3)+(x<<1)+(c^48),c=getchar();
		if(neg) x=(~x)+1;
	}
	template<typename T> void recursive_print(T x){return (!x)?void():(recursive_print(x/10),putc(x%10^48),void());}
	template<typename T> void print(T x){(!x)&&(putc('0'),0);(x<0)&&(putc('-'),x=~x+1);recursive_print(x);}
	template<typename T> void print(T x,char c){(!x)&&(putc('0'),0);(x<0)&&(putc('-'),x=~x+1);recursive_print(x);putc(c);}
	void print_final(){fwrite(wbuf,1,p3-wbuf,stdout);}
}
const int MAXN=600;
const int MOD=1e9+7;
int n,a[MAXN+5],vis[MAXN+5],id[MAXN+5],m=0,is[MAXN+5];
int dp[MAXN+5][MAXN+5][MAXN+5];
void add(int &x,int v){((x+=v)>=MOD)&&(x-=MOD);}
int main(){
	scanf("%d",&n);
	for(int i=1;i<=n<<1;i++) scanf("%d",&a[i]);
	for(int i=1;i<=n<<1;i+=2) if(~a[i]&&~a[i+1]) vis[a[i]]=vis[a[i+1]]=1;
	for(int i=1;i<=n<<1;i++) if(!vis[i]) id[i]=++m;
	for(int i=1;i<=n<<1;i+=2){
		if(~a[i]&&!~a[i+1]) is[id[a[i]]]=1;
		if(!~a[i]&&~a[i+1]) is[id[a[i+1]]]=1;
	} dp[m+1][0][0]=1;
//	for(int i=1;i<=m;i++) printf("%d\n",is[i]);
	for(int i=m;i;i--) for(int j=0;j<=m-i;j++) for(int k=0;k+j<=m-i;k++){
		if(is[i]){
			add(dp[i][j][k+1],dp[i+1][j][k]);
			if(j) add(dp[i][j-1][k],dp[i+1][j][k]);
		} else {
			add(dp[i][j+1][k],dp[i+1][j][k]);
			if(k) add(dp[i][j][k-1],1ll*dp[i+1][j][k]*k%MOD);
			if(j) add(dp[i][j-1][k],dp[i+1][j][k]);
		} //printf("%d %d %d %d\n",i,j,k,dp[i][j][k]);
	} int res=dp[1][0][0];
	int cc=0;for(int i=1;i<=(n<<1);i+=2) cc+=((!~a[i])&&(!~a[i+1]));
	for(int i=1;i<=cc;i++) res=1ll*res*i%MOD;
	printf("%d\n",res);
	return 0;
}
/*
6
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
*/

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:41:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   41 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
./Main.cpp:42:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   42 |  for(int i=1;i<=n<<1;i++) scanf("%d",&a[i]);
      |                           ~~~~~^~~~~~~~~~~~

Judge Result