【題解】AtCoder ABC 167B – Easy Linear Programming

#include <iostream>
using namespace std;

int a, b, c, k, ans;

int main() {
    cin >> a >> b >> c >> k;
    if (k){
        ans += min(k, a);
        k -= min(k, a);
    }
    if (k){
        k -= min(k, b);
    }
    if (k){
        ans -= min(k, c);
        k -= min(k, c);
    }
    cout << ans << "\n";
}