pat1065 A+B and C (64bit)

题意：输入a,b,c三个数，问a+b是否大于c。

思路：输入在long long范围内，只要考虑上溢和下溢的情况即可。

代码

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>

using namespace std;

typedef long long ll;

int n;
ll a, b, c;

int main() {
    // freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> a >> b >> c;
        cout << "Case #" << i << ": ";
        ll res = a + b;
        bool flag;
        if (a>0&&b>0&&res<=0) flag = true;
        else if (a<=0&&b<0&&res>=0) flag = false;
        else if (res>c) flag = true;
        else flag = false;
        if (flag) cout << "true" << endl;
        else cout << "false" << endl;
    }
    return 0;
}