Submission #469165

#	Time	Username	Problem	Language	Result	Execution time	Memory
469165		Cross_Ratio	Strange Device (APIO19_strange_device)	C++14	65 / 100	1056 ms	48304 KiB

strange_device

#include <bits/stdc++.h>
#define int long long
using namespace std;
int gcd(int a, int b) {
    a = abs(a);
    b = abs(b);
    if(a < b) swap(a, b);
    while(b) {
        a %= b;
        swap(a, b);
    }
    return a;
}
vector<int> B;
int getidx(int n) {
    return lower_bound(B.begin(),B.end(),n) - B.begin();
}
struct SegTree {
    vector<int> seg;
    int MAX;
    SegTree(int N) {
        int i;
        for(i=2;i<2*N;i*=2) {}
        seg.resize(i);
        MAX = i;
    }
    int sum(int s, int e, int n, int ns, int ne) {
        if(e<=ns||ne<=s) return 0;
        if(s<=ns&&ne<=e) return seg[n];
        int mid = ns + ne >> 1;
        return sum(s, e, 2*n, ns, mid) + sum(s, e, 2*n+1, mid, ne);
    }
    void update(int n) {
        n += MAX/2;
        n /= 2;
        while(n) {
            seg[n] = seg[2*n] + seg[2*n+1];
            n /= 2;
        }
    }
    void Plus(int n) {
        seg[n+MAX/2]++;
        update(n);
    }
    void Minus(int n) {
        seg[n+MAX/2]--;
        update(n);
    }
    int sum(int s, int e) {
        return sum(s, e, 1, 0, MAX/2);
    }
};
int L[1000005];
int R[1000005];
main() {
    cin.sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int N, a, b;
    cin >> N >> a >> b;
    int d = gcd(a, b + 1);
    int c = a / d;
    assert(a % d == 0);
    int k = b * c;
    int l, r;
    bool isAll = false;
    int i;
    B.push_back(0);
    B.push_back(k);
    for(i=0;i<N;i++) {
        cin >> L[i] >> R[i];
        if(R[i] - L[i] >= k-1) isAll = true;
        L[i] %= k;
        R[i] %= k;
        R[i]++;
        B.push_back(L[i]);
        B.push_back(R[i]);
    }
    sort(B.begin(),B.end());
    B.erase(unique(B.begin(),B.end()),B.end());
    SegTree tree(B.size() + 10);
    for(i=0;i<N;i++) {
        int l = getidx(L[i]);
        int r = getidx(R[i]);
        if(l < r) {
            tree.Plus(l);
            tree.Minus(r);
        }
        else {
            tree.Plus(0);
            tree.Minus(r);
            tree.Plus(l);
            tree.Minus(B.size());
        }
    }
    int cnt = 0;
    for(i=0;i<B.size()-1;i++) {
        if(tree.sum(0,i+1)!=0) {
            cnt += B[i+1]-B[i];
        }
    }
    //cnt = isAll ? k : cnt;
    cout << cnt;
}

Compilation message (stderr)

strange_device.cpp: In member function 'long long int SegTree::sum(long long int, long long int, long long int, long long int, long long int)':
strange_device.cpp:30:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   30 |         int mid = ns + ne >> 1;
      |                   ~~~^~~~
strange_device.cpp: At global scope:
strange_device.cpp:55:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   55 | main() {
      | ^~~~
strange_device.cpp: In function 'int main()':
strange_device.cpp:97:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   97 |     for(i=0;i<B.size()-1;i++) {
      |             ~^~~~~~~~~~~
strange_device.cpp:65:9: warning: unused variable 'l' [-Wunused-variable]
   65 |     int l, r;
      |         ^
strange_device.cpp:65:12: warning: unused variable 'r' [-Wunused-variable]
   65 |     int l, r;
      |            ^
strange_device.cpp:66:10: warning: variable 'isAll' set but not used [-Wunused-but-set-variable]
   66 |     bool isAll = false;
      |          ^~~~~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
• Subtask 6: 20 / 20
• Subtask 7: 20 / 20
• Subtask 8: 0 / 30