题目

Given three integers A, B and C in [-2⁶³, 2⁶³], you are supposed to tell whether A+B > C.

Input Specification:

The first line of the input gives the positive number of test cases, T (<=10).  Then T test cases follow, each consists of a single line containing three integers A, B and C, separated by single spaces.

Output Specification:

For each test case, output in one line "Case #X: true" if A+B>C, or "Case #X: false" otherwise, where X is the case number (starting from 1).

Sample Input:

3

1 2 3

2 3 4

9223372036854775807 -9223372036854775808 0

Sample Output:

Case #1: false

Case #2: true

Case #3: false

须要考A+B虑溢出的问题。可能是上界。也可能是下界。

能够考虑string模拟大数的方法，代码用了一种适用于两个元素的投机方法。

代码：

#include <iostream>

using namespace std;

int main()

{

	int n;

	cin>>n;

	long long a,b,c;

	int i,j;

	for(i=0;i<n;i++)	//一种投机取巧的办法。仅适用于两个元素

	{

		cin>>a>>b>>c;

		cout<<"Case #"<<i+1<<": ";

		if(a>0&&b>0&&a+b<a&&a+b<b)	//上越界，必定大于c

			cout<<"true\n";

		else if(a<0&&b<0&&a+b>a&&a+b>b)	//下越界，必定小于c

			cout<<"false\n";

		else if(a+b>c)	//常规比較

			cout<<"true\n";

		else

			cout<<"false\n";

	}

	return 0;

}