PAT

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:

31 2 32 3 49223372036854775807 -9223372036854775808 0

Sample Output:

Case #1: falseCase #2: trueCase #3: false

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给定条件：
1.long long 范围的数 a b 和 c

要求：
1.a+b 是否大于 c

求解：
方法1:
1.利用数组模拟大数相加减

方法2:
1.由于不求结果，只看a+b是否大于c，所以可以考虑可能出现的情况分类讨论即可
1.1.a和b一正一负 可以直接计算比较
1.2.a和b都为正，如果结果溢出，则一定比c大，否则可直接比较大小
1.3.a和b都为负，如果结果溢出，则一定比c小，否则可直接比较大小

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#include <cstdio>using namespace std;int t;long long a, b, c;int main() {scanf("%d", &t);for(int i = 0; i < t; i++) {printf("Case #%d: ", i+1);scanf("%lld%lld%lld", &a, &b, &c);long long sum = a + b;if(a > 0 && b > 0 && sum < 0) printf("true\n");else if(a < 0 && b < 0 && sum >= 0)printf("false\n");else if(sum > c)printf("true\n");elseprintf("false\n");}return 0;}

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