#include <bits/stdc++.h>
using namespace std;
int mopd=1000000007;
int a[300001];
int s[300001];
int main() {
int n;
scanf("%d",&n); bool small=true;
for(int i=0; i < n; ++i) {
scanf("%d",a+i);
if(a[i] > 300) small=false;
}
if(small) {
int parsum, nparsum;
if(a[0] % 2==0) { s[0]=1; parsum=1; nparsum=0; }
else { s[0]=0; nparsum=1; parsum=0; }
for(int j=1; j<n; ++j) {
//wylicz s[j]:
if(a[j]%2==0) {
parsum+=s[j-1];
parsum%=mopd;
s[j]=parsum;
}
else {
s[j]=nparsum;
swap(parsum,nparsum);
nparsum+=s[j-1];
nparsum%=mopd;
}
}
printf("%d\n",s[n-1]);
return 0;
}
if(a[0]%2==0) s[0]=1;
else s[0]=0;
for(int j=1; j<n; ++j) {
int sum=a[j]; s[j]=0;
for(int count=1; count <= j; count++) {
if(sum % 2 == 0) {
s[j]+=s[j-count];
s[j]%=mopd;
}
sum+=a[j-count];
sum%=mopd;
}
if(sum%2==0) { s[j]+=1; s[j]%=mopd; }
}
printf("%d\n",s[n-1]);
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | #include <bits/stdc++.h> using namespace std; int mopd=1000000007; int a[300001]; int s[300001]; int main() { int n; scanf("%d",&n); bool small=true; for(int i=0; i < n; ++i) { scanf("%d",a+i); if(a[i] > 300) small=false; } if(small) { int parsum, nparsum; if(a[0] % 2==0) { s[0]=1; parsum=1; nparsum=0; } else { s[0]=0; nparsum=1; parsum=0; } for(int j=1; j<n; ++j) { //wylicz s[j]: if(a[j]%2==0) { parsum+=s[j-1]; parsum%=mopd; s[j]=parsum; } else { s[j]=nparsum; swap(parsum,nparsum); nparsum+=s[j-1]; nparsum%=mopd; } } printf("%d\n",s[n-1]); return 0; } if(a[0]%2==0) s[0]=1; else s[0]=0; for(int j=1; j<n; ++j) { int sum=a[j]; s[j]=0; for(int count=1; count <= j; count++) { if(sum % 2 == 0) { s[j]+=s[j-count]; s[j]%=mopd; } sum+=a[j-count]; sum%=mopd; } if(sum%2==0) { s[j]+=1; s[j]%=mopd; } } printf("%d\n",s[n-1]); return 0; } |
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