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Submission #227645

# Submission time Handle Problem Language Result Execution time Memory
227645 2020-04-28T08:51:25 Z imsifile Ruins 3 (JOI20_ruins3) C++
58 / 100
 6000 ms 3496 KB 
#include<stdio.h>

typedef long long lld;
const lld mod=1000000007;

int N, chk[1212], pos[666], neg[666];
lld dy[666][666], pw[1212], fac[1212], rfac[1212], rgop[1212], all[666];

int cc[666], ba[666], tmp[666], rcn[666];

lld rev(lld a){
	lld g=1;
	for(int r=mod-2; r; r>>=1){
		if(r&1) g=g*a%mod;
		a=a*a%mod;
	}
	return g;
}

lld perm(lld a, lld b){
	if(a<b) return 0;
	return fac[a]*rfac[a-b]%mod;
}

int main(){
	scanf("%d", &N);
	for(int i=1; i<=2*N; i++) chk[i]=1;
	pw[0]=fac[0]=rfac[0]=1;
	for(int i=1; i<=2*N; i++){
		pw[i]=pw[i-1]*((mod+1)/2)%mod;
		fac[i]=fac[i-1]*i%mod;
		rfac[i]=rev(fac[i]);
		rgop[i]=rev(4*i-2);
	}
	for(int i=1; i<=N; i++){
		if(i==1) all[i]=1;
		else all[i]=fac[2*i]*pw[i]%mod*rgop[i]%mod*rfac[i]%mod*rfac[i]%mod;
	}

	for(int i=0; i<N; i++){
		scanf("%d", &neg[i]);
		chk[neg[i]]=-1;
	}
	for(int i=1, pcn=0; i<=2*N; i++){
		if(chk[i]>0) pos[pcn++]=i;
		chk[i]+=chk[i-1];
		if(chk[i]<0){ puts("0"); return 0; }
	}
	for(int i=N; i>=0; i--){
		for(int j=i; j>=0; j--){
			if(i==N && j==N) dy[i][j]=1;
			else if(i==N || pos[i]>neg[j]) dy[i][j]=dy[i][j+1]*chk[neg[j]-1]%mod;
			else {
				for(int must=0; must<=i-j; must++){
					int x=chk[neg[j+must]-1]+j+must-i, y=0;
					if(must) y=chk[neg[j+must-1]-1]+j+must-1-i;
					if(x==y) continue;
					for(int k=1; k<=x; k++){
						lld pm=(perm(x,k)-perm(y,k)+mod)*perm(i-j,must)%mod;
						dy[i][j]+=dy[i+k][j+must]*all[k]%mod*pm%mod;
					}
				}
				dy[i][j]%=mod;
			}
		}
	}
	printf("%lld\n", dy[0][0]);
	return 0;
}

Compilation message

ruins3.cpp: In function 'int main()':
ruins3.cpp:26:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
  ~~~~~^~~~~~~~~~
ruins3.cpp:41:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &neg[i]);
   ~~~~~^~~~~~~~~~~~~~~

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Correct 5 ms 384 KB Output is correct
4 Correct 4 ms 384 KB Output is correct
5 Correct 4 ms 384 KB Output is correct
6 Correct 4 ms 384 KB Output is correct
7 Correct 4 ms 384 KB Output is correct
8 Correct 4 ms 384 KB Output is correct
9 Correct 4 ms 384 KB Output is correct
10 Correct 4 ms 384 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Correct 5 ms 384 KB Output is correct
4 Correct 4 ms 384 KB Output is correct
5 Correct 4 ms 384 KB Output is correct
6 Correct 4 ms 384 KB Output is correct
7 Correct 4 ms 384 KB Output is correct
8 Correct 4 ms 384 KB Output is correct
9 Correct 4 ms 384 KB Output is correct
10 Correct 4 ms 384 KB Output is correct
11 Correct 5 ms 640 KB Output is correct
12 Correct 4 ms 640 KB Output is correct
13 Correct 5 ms 640 KB Output is correct
14 Correct 4 ms 384 KB Output is correct
15 Correct 4 ms 384 KB Output is correct
16 Correct 5 ms 640 KB Output is correct
17 Correct 4 ms 384 KB Output is correct
18 Correct 5 ms 640 KB Output is correct
19 Correct 7 ms 640 KB Output is correct
20 Correct 7 ms 640 KB Output is correct

Subtask #3
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 384 KB Output is correct
2 Correct 4 ms 384 KB Output is correct
3 Correct 5 ms 384 KB Output is correct
4 Correct 4 ms 384 KB Output is correct
5 Correct 4 ms 384 KB Output is correct
6 Correct 4 ms 384 KB Output is correct
7 Correct 4 ms 384 KB Output is correct
8 Correct 4 ms 384 KB Output is correct
9 Correct 4 ms 384 KB Output is correct
10 Correct 4 ms 384 KB Output is correct
11 Correct 5 ms 640 KB Output is correct
12 Correct 4 ms 640 KB Output is correct
13 Correct 5 ms 640 KB Output is correct
14 Correct 4 ms 384 KB Output is correct
15 Correct 4 ms 384 KB Output is correct
16 Correct 5 ms 640 KB Output is correct
17 Correct 4 ms 384 KB Output is correct
18 Correct 5 ms 640 KB Output is correct
19 Correct 7 ms 640 KB Output is correct
20 Correct 7 ms 640 KB Output is correct
21 Correct 25 ms 3456 KB Output is correct
22 Correct 21 ms 3456 KB Output is correct
23 Correct 18 ms 3456 KB Output is correct
24 Correct 72 ms 3444 KB Output is correct
25 Correct 5 ms 384 KB Output is correct
26 Correct 5 ms 384 KB Output is correct
27 Correct 5 ms 384 KB Output is correct
28 Correct 8 ms 3456 KB Output is correct
29 Correct 5 ms 384 KB Output is correct
30 Correct 500 ms 3496 KB Output is correct
31 Execution timed out 6067 ms 2012 KB Time limit exceeded
32 Halted 0 ms 0 KB -