\(f(i)=f(i-1)+i (0 \le i \le 34567890, f(0)=1 )\)

#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <vector>
#include <deque>
using namespace std;

namespace dts
{
    typedef long long ll;
    
    ll n;
    
    void main()
    {
        scanf("%lld",&n);
        printf("%lld\n",n*(n+1)/2+1);
    }
};

int main()
{
    dts::main();
}

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <algorithm>
using namespace std;
int main()
{
    int a,i;
    long long c=1;
    scanf("%d",&a);
    for(i=1;i<=a;i++)
    {
        c=c+i;
    }
    printf("%lld",c);
    return 0;
}

#include<bits/stdc++.h>
using namespace std;

int main()
{
int a,b;
long long c=0;
cin>>a;
for(b=1;b<=a;b++){
c=c+b;
}
cout<<c+1;
return 0;
}

我的题解

AC100纪念

评测结果
编译成功

测试数据 #0: Accepted, time = 15 ms, mem = 812 KiB, score = 10
测试数据 #1: Accepted, time = 0 ms, mem = 812 KiB, score = 10
测试数据 #2: Accepted, time = 0 ms, mem = 816 KiB, score = 10
测试数据 #3: Accepted, time = 0 ms, mem = 812 KiB, score = 10
测试数据 #4: Accepted, time = 0 ms, mem = 812 KiB, score = 10
测试数据 #5: Accepted, time = 15 ms, mem = 812 KiB, score = 10
测试数据 #6: Accepted, time = 15 ms, mem = 816 KiB, score = 10
测试数据 #7: Accepted, time = 31 ms, mem = 820 KiB, score = 10
测试数据 #8: Accepted, time = 62 ms, mem = 816 KiB, score = 10
测试数据 #9: Accepted, time = 62 ms, mem = 816 KiB, score = 10
Accepted, time = 200 ms, mem = 820 KiB, score = 100
###代码
program cut;
var
i,n:longint;
a:int64;
begin
readln(n);
a:=1;
for i:=1 to n do a:=a+i;
writeln(a);
end.

其实主要就是范围问题……答案要用_int64_

#include<iostream>
using namespace std;
__int64 n,f;
int main()
{
cin>>n;
f=n*(n+1)/2+1;
cout<<f<<endl;
return 0;
}
AC60纪念

水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水水
纪念vijios第三道不用数组的题

var n,k:longint;s:int64;
begin
readln(n);k:=0;s:=1;
while k<>n do begin inc(k);s:=s+k;end;
writeln(s);
end.

var
n,m:int64;
begin
readln(n);
m:=1+(n*(n+1)) shr 1;
writeln(m);
end.
经典的简单数学题。。。

简单啊！！！

评测结果
编译成功

foo.pas(5,8) Warning: Variable "i" does not seem to be initialized
foo.pas(8,6) Warning: Variable "k" does not seem to be initialized

测试数据 #0: Accepted, time = 0 ms, mem = 824 KiB, score = 10

测试数据 #1: Accepted, time = 0 ms, mem = 820 KiB, score = 10

测试数据 #2: Accepted, time = 0 ms, mem = 820 KiB, score = 10

测试数据 #3: Accepted, time = 0 ms, mem = 824 KiB, score = 10

测试数据 #4: Accepted, time = 0 ms, mem = 820 KiB, score = 10

测试数据 #5: Accepted, time = 46 ms, mem = 824 KiB, score = 10

测试数据 #6: Accepted, time = 31 ms, mem = 820 KiB, score = 10

测试数据 #7: Accepted, time = 93 ms, mem = 820 KiB, score = 10

测试数据 #8: Accepted, time = 125 ms, mem = 824 KiB, score = 10

测试数据 #9: Accepted, time = 140 ms, mem = 824 KiB, score = 10

Accepted, time = 435 ms, mem = 824 KiB, score = 100

代码
var i,k,l,n:int64;
begin
l:=1;
read(n);
while i<>n do
begin
i:=i+1;
k:=k+1;
l:=l+k;
end;
writeln(l);
end.

PYTHON:

a=int(raw_input())
print a*(a+1)/2+1

AC 30题纪念~ 好简单。。。

水题

。。。

坑爹~你这是切饼啊还是切蛋糕啊~Orz...

五行代码

秒杀一切！！！

var n:int64;

begin

readln(n);

write(1+(n*(n+1))div 2);

end.

注意结果很大！！！

longint会爆

program vijos_1324;

var

n,i:longint;

a:int64;

begin

readln(n);

a:=1;

for i:=1 to n do

a:=a+i;

writeln(a);

end.

真不是一般水。。。

#include

using namespace std;

int main ()

{

unsigned long long n;

cin>>n;

cout

本菜菜菜菜鸟AC50题!

首先，由于大多数人拷贝题解（程序很短）通过人数飙升

第二，我到现在还没有过.....