牛客小白月赛9

https://ac.nowcoder.com/acm/contest/275?&headNav=www#rank

A：签到

大佬代码：

include<bits/stdc++.h>

using namespace std;
#define P 1000000007
#define ll long long
int n,i,a,b,ans,I[100005];
int main()
{
for(I[1]=1,i=2;i<100005;i++)I[i]=(ll)(P-P/i)I[P%i]%P;
scanf("%d",&n);
ans=1;
while(n--)
{
scanf("%d%d",&a,&b);
ans=(ll)ans(b-a)%P*I[b]%P;
}
cout<<(P+1-ans)%P<<endl;
return 0;
}

大佬代码：

include

include

include

define MOD 1000000007

using namespace std;

typedef long long ll;

ll pow_mod(ll x,int k) {
ll ans=1;
while (k) {
if (k&1) ans=ansx%MOD;
x=xx%MOD;
k>>=1;
}
return ans;
}

int main() {
int n;
scanf("%d",&n);
ll ans=1;
for(int i=1;i<=n;i++) {
int x,y;
scanf("%d%d",&x,&y);
ans=ans(1LL-xpow_mod(y,MOD-2)%MOD+MOD)%MOD;
}
printf("%lld\n",(1LL-ans+MOD)%MOD);
return 0;
}

大佬代码：

include

const int mod = 1000000007;
typedef long long LL;
int qPow(int b,int e){
int a=1;
for(;e;e>>=1,b=(LL)bb%mod) if(e&1) a=(LL)ab%mod;
return a;
}
int n;
int main(){
int Ans=1;
scanf("%d",&n);
for(int i=1;i<=n;++i) {
int a,b;
scanf("%d%d",&a,&b);
a=b-a;
Ans=(LL)Ansa%modqPow(b,mod-2)%mod;
}
printf("%d",(1+mod-Ans)%mod);
return 0;
}

B：法法

大佬代码：

include<bits/stdc++.h>

using namespace std;
int t;
long long n;
int main()
{
cin>>t;
while(t--)
{
cin>>n;
cout<<(n<3)<<endl;
}
return 0;
}

大佬代码：

include

include

include

using namespace std;

typedef long long ll;

int main() {
int cases;
scanf("%d",&cases);
for(;cases;cases--) {
ll n;
scanf("%lld",&n);
puts((n>2)?"0":"1");
}
return 0;
}

大佬代码：

include

int main(){
int T;
scanf("%d",&T);
while(T--){
long long n;
scanf("%lld",&n);
if(n<=2) puts("1");
else puts("0");
}
}

C：红球进黑洞

D：树上求和

E：换个角度思考

F：暴力出奇迹

G：简单

H：论如何出一道水题

I：给给

J:div.2 A