Submission #1678172

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Source Code Expand

#include <cstdio>
#include <cstring>
#include <algorithm>
#define MAXN 110
#define LL long long
using namespace std;

const LL P=1000000007;

int n,n2;
int a[MAXN];
int next_v[MAXN],prev_v[MAXN];
LL f[MAXN][MAXN][MAXN][2];

inline void update(LL &x,LL y){ x=(x+y)%P; }

int main(){
#ifdef DEBUG
	freopen("F.in","r",stdin);
#endif
	scanf("%d",&n);
	n2=n*2-1;
	for(int i=1;i<=n2;i++) scanf("%d",a+i);
	sort(a+1,a+n2+1);
	for(int i=2;i<=n2;i++)
		if(a[i-1]!=a[i]){
			next_v[a[i-1]]=a[i];
			prev_v[a[i]]=a[i-1];
		}
	prev_v[a[1]]=-1;
	next_v[a[n2]]=n2+1;
	f[0][a[1]][a[n2]][0]=1;
	for(int i=0;i<n;i++){
		int lpos=i+1,rpos=n2-i;
		for(int j=a[1];j<=a[n2];j=next_v[j])
			for(int k=j;k<=a[n2];k=next_v[k]){
				if(f[i][j][k][0]){
					for(int l=j;l<=k;l=next_v[l])
						if(l>=a[lpos] && l<=a[rpos]){
							update(f[i+1][j][l][0],f[i][j][k][0]);
							update(f[i+1][l][k][1],f[i][j][k][0]);
						}
				}
				if(f[i][j][k][1]){
					for(int l=j;l<=k;l=next_v[l])
						if(l>=a[lpos] && l<=a[rpos]){
							if(l==j){
								update(f[i+1][l][k][1],f[i][j][k][1]);
							}else{
								update(f[i+1][j][l][0],f[i][j][k][1]);
								update(f[i+1][l][k][1],f[i][j][k][1]);
							}
						}
				}
			}
	}
	LL ans=0;
	for(int i=1;i<=n2;i++)
		for(int j=1;j<=n2;j++)
			update(ans,f[n][i][j][0]);
	printf("%lld\n",ans);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:21:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
./Main.cpp:23:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1;i<=n2;i++) scanf("%d",a+i);
                                        ^

Judge Result