Submission #128537

#	Time	Username	Problem	Language	Result	Execution time	Memory
128537		ae04071	Strange Device (APIO19_strange_device)	C++11	100 / 100	923 ms	34684 KiB

strange_device

#include <bits/stdc++.h>
using namespace std;
using lli = long long;

const lli INF = 2e18;
lli mul(lli a,lli b) {
    if(a>=INF || b>=INF || INF/a<b) return INF;
    else return min(INF, a*b);
}
int main() {
    int n;
    lli A,B;
    scanf("%d%lld%lld",&n,&A,&B);

    lli g = __gcd(A-1,B), s = abs(B-A+1) / g;
    lli kg = __gcd(s, A), k = A / kg;
    //lli I = mul(k, B/g);
    lli I = mul(mul(k, B/g), g);

    vector<pair<lli,int>> arr;
    for(int i=0;i<n;i++) {
        lli l,r;
        scanf("%lld%lld",&l,&r);
        if(r-l+1>=I) {
            arr.push_back({0,1});
            arr.push_back({I,-1});
        } else {
            l%=I; r%=I;
            if(l<=r) {
                arr.push_back({l,1});
                arr.push_back({r+1,-1});
            } else {
                arr.push_back({0,1});
                arr.push_back({r+1,-1});
                arr.push_back({l,1});
                arr.push_back({I,-1});
            }
        }
    }
    
    lli ans=0,ad=0,pr=0;
    sort(arr.begin(),arr.end());
    for(int i=0,j=0;i<(int)arr.size();i=j) {
        ans += (arr[i].first - pr) * min(ad, 1ll);
        for(j=i;j<(int)arr.size() && arr[i].first==arr[j].first;j++) {
            ad += arr[j].second;
        }
        pr = arr[i].first;
    }
    printf("%lld\n",ans);
    
    return 0;
}

Compilation message (stderr)

strange_device.cpp: In function 'int main()':
strange_device.cpp:13:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%lld%lld",&n,&A,&B);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
strange_device.cpp:23:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%lld%lld",&l,&r);
         ~~~~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
• Subtask 6: 20 / 20
• Subtask 7: 20 / 20
• Subtask 8: 30 / 30