POJ 2924 Gauß in Elementary School（水~）

Description
给出两个数s和e，输出s+…+e
Input
第一行为用例组数t，每组用例占一行包括两个整数s和e(-10^9<=s,e<=10^9)
Output
Sample Input
3
1 100
-11 10
-89173 938749341
Sample Output

Scenario #1:
5050

Scenario #2:
-11

Scenario #3:
440625159107385260
Solution
水题
Code

#include<stdio.h>typedef long long ll;int main(){    int n,res=1;    ll s,e,ss,ee;    scanf("%d",&n);    while(n)    {        scanf("%lld%lld",&s,&e);        ss=s>=0?s:-s;        ee=e>=0?e:-e;        if(s>0&&e>0)        {            ss=(ss-1)*ss/2;            ee=(ee+1)*ee/2;        }        else if(s<=0&&e>=0)            {                ss=(ss+1)*ss/2;                ee=(ee+1)*ee/2;             }            else if(s<0&&e<0)                {                    ss=(ss+1)*ss/2;                    ee=(ee-1)*ee/2;                }        printf("Scenario #%d:\n",res);        printf("%lld\n\n",ee-ss);        res++;        n--;    }    return 0;}