1065 A+B and C (64bit) (20分)
Given three integers A, B and C in [−], 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 (≤). 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
数据范围是long long的范围，则a + b可能会产生正负溢出。
若令sum = a + b，
如果a > 0 且b > 0,则sum溢出之后的取值范围为[(1 << 63)(这个数是longlong能表示的最大负数), -2];
a < 0 且 b < 0溢出时，范围是[0, (1 << 63) - 1];
1 #include <cstdio> 2 using namespace std; 3 4 typedef long long ll; 5 6 int main() { 7 ll a, b, c; 8 int t; 9 scanf("%d", &t); 10 int _case = 0; 11 bool flag; 12 while(t --) { 13 scanf("%lld %lld %lld", &a, &b, &c); 14 ll sum = a + b; 15 if(a > 0 && b > 0 && sum < 0) flag = true; 16 else if(a < 0 && b < 0 && sum >= 0) flag = false; 17 else if(sum > c) flag = true; 18 else flag = false; 19 printf("Case #%d: ", ++ _case); 20 if(flag) printf("true "); 21 else printf("false "); 22 } 23 return 0; 24 }