the sum of cube 立方和

A range is given, the begin and the end are both integers. You should sum the cube of all the integers in the range.InputThe first line of the input is T(1 <= T <= 1000), which stands for the number of test cases you need to solve. Each case of input is a pair of integer A,B(0 < A <= B <= 10000),representing the rangeA,BA,B.OutputFor each test case, print a line “Case #t: ”(without quotes, t means the index of the test case) at the beginning. Then output the answer �C sum the cube of all the integers in the range.Sample Input

2
1 3
2 5

Sample Output

Case #1: 36
Case #2: 224

两种解法

公式不会推百度的

#include<cstdio>int main(){int t;scanf("%d",&t);for (int k=1;k<=t;++k){long long s,d;scanf("%lld%lld",&s,&d);/*long long sum=0;for (long long i=s;i<=d;++i){sum+=i*i*i;}printf("Case #%d: %lld\n",k,sum);*/printf("%lld\n",(d*(d+1)/2)*(d*(d+1)/2)-(s*(s-1)/2)*(s*(s-1)/2));}return 0;}