上午测试讲题
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#include<bits/stdc++.h>
using namespace std;
int n;
int main(){
cin>>n;
int s1=0, s2=1;
for(int i=1; i<=n; i++){
s1 += i;
s2 *= i;
}
// s1 = (1+n) * n / 2;
cout<<s1<<endl<<s2<<endl;
return 0;
}
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#include<bits/stdc++.h> // 万能头
using namespace std;
int n;
int main(){
int a,b; cin>>a>>b;
int la=0,lb=0;
int ta=a, tb=b;
while(ta) { la ++; ta/=10; }
while(tb) { lb ++; tb/=10; }
if(la < lb) a *= pow(10, lb-la);
if(la > lb) b *= pow(10, la-lb);
cout<<a+b;
return 0;
}
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#include<bits/stdc++.h>
using namespace std;
const int N=110;
int n, a[N];
int main(){
cin>>n;
for(int i=1; i<=n; i++) cin>>a[i];
// flag=1 是等差数列, 0不是等差数列
int d = a[1], flag=1;
if(n>2) d = a[2]-a[1];
for(int i=2; i<=n; i++){
if(a[i]-a[i-1]!=d) {
flag=0; break;
}
}
if(flag) cout<<1ll *(a[1] + a[n]) * n/2;// 注意爆 int
else cout<<0;
return 0;
}
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#include<bits/stdc++.h>
using namespace std;
const int N=110;
int f[N], ans;
int main(){
int a,b,n,i,j;
cin>>a>>b>>n>>i>>j;
int q = sqrt(b/a);
f[1]=a;
for(int k=2; k<=n; k++) f[k]=f[k-1] * q; // 构造等比数列
for(int k=i; k<=j; k++){
cout<<f[k]<<" ";
ans += f[k];
}
cout<<endl<<ans;
return 0;
}
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#include<bits/stdc++.h>
using namespace std;
const int N=110;
char s[N];
int main(){
cin>>s;
int n = strlen(s), sum=0, p=1;
for(int i=0; i<n-1; i++)
if(isdigit(s[i])){
sum += (s[i]-'0') * p; p++;
}
sum %= 11;
int c = s[n-1]-'0';
if(sum < 10 && c==sum || sum==10 && s[n-1]=='X') cout<<"Right";
else {
if(sum<10) s[n-1] = sum +'0';
else s[n-1] = 'X';
cout<<s;
}
return 0;
}
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#include<bits/stdc++.h>
using namespace std;
const int N=110;
int n,x,st[10];
int main(){
cin>>n>>x;
for(int i=1; i<=n; i++){
int t=i;
while(t) st[t%10] ++, t/=10;
}
cout<<st[x];
return 0;
}
下午一维数组
https://www.cnblogs.com/hellohebin/p/15170336.html