Submission #145176

#	Time	Username	Problem	Language	Result	Execution time	Memory
145176		solimm4sks	Watching (JOI13_watching)	C++14	0 / 100	1078 ms	49664 KiB

watching

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

long long n, p, q;
long long a[200005];

/*
bool check(long long w){

    long long smallCam = p;
    long long bigCam = q;
    for(long long i = 0; i < n; ++i){
        long long ind1 = upper_bound(a, a + n, a[i] + w - 1) - a;
        long long ind2 = upper_bound(a, a + n, a[i] + 2 * w - 1) - a;

        if(ind2 > ind1){
            if(bigCam){
                bigCam--;
                i = ind2 - 1;
                continue;
            }
        }

        if(smallCam){
            smallCam--;
            i = ind1 - 1;
        }else if(bigCam){
            bigCam--;
            i = ind2 - 1;
        }else{
            return false;
        }
    }

    return true;
}
*/

bool cmp(pair<long long, long long> x, pair<long long, long long> y){
    return (x.second - x.first + 1) > (y.second - y.first + 1); ///sort, by real dist, or index dist?
}

long long st[8005];
long long lazy[8005];

void updNode(long long val, long long id, long long l, long long r){
    lazy[id] += val;
    st[id] += (r - l + 1) * val;
}

void shift(long long id, long long l, long long r){
    long long mid = (l + r) / 2;
    updNode(lazy[id], id * 2 + 1, l, mid);
    updNode(lazy[id], id * 2 + 2, mid + 1, r);
    lazy[id] = 0;
}

void update(long long x, long long y, long long val, long long id, long long l, long long r){
    if(x > r || y < l){
        return;
    }
    if(x <= l && r <= y){
        updNode(val, id, l, r);
        return;
    }

    shift(id, l, r);
    long long mid = (l + r) / 2;
    update(x, y, val, id * 2 + 1, l, mid);
    update(x, y, val, id * 2 + 2, mid + 1, r);

    st[id] = st[id * 2 + 1] + st[id * 2 + 2];
}

long long gSum(long long x, long long y, long long id, long long l, long long r){
    if(x > r || y < l){
        return 0;
    }
    if(x <= l && r <= y){
        return st[id];
    }
    shift(id, l, r);
    long long mid = (l + r) / 2;
    long long v1 = gSum(x, y, id * 2 + 1, l, mid);
    long long v2 = gSum(x, y, id * 2 + 2, mid + 1, r);

    return v1 + v2;
}

void build(long long id, long long l, long long r){
    if(l == r){
        st[id] = 0;
        lazy[id] = 0;
        return;
    }

    long long mid = (l + r) / 2;
    build(id * 2 + 1, l, mid);
    build(id * 2 + 2, mid + 1, r);

    st[id] = 0;
    lazy[id] = 0;
}

bool check(long long w){
    build(0, 0, n - 1);

    vector<pair<long long, long long>> prs;
    for(long long i = 0; i < n; ++i){
        for(long long j = i; j < n; ++j){
            prs.push_back({i, j});
        }
    }

    long long numBig = q;
    long long numSmall = p;

    sort(prs.begin(), prs.end(), cmp);
    for(long long i = 0; i < (long long)prs.size(); ++i){
        long long x = prs[i].first;
        long long y = prs[i].second;
        long long val = gSum(x, y, 0, 0, n - 1);
        if(val){
            continue;
        }
        if(a[y] - a[x] + 1 <= 2 * w){
            if(numBig){
                numBig--;
                update(x, y, 1, 0, 0, n - 1);
            }else if(numSmall && a[y] - a[x] + 1 <= w){
                numSmall--;
                update(x, y, 1, 0, 0, n - 1);
            }
        }
    }

    long long ttSum = gSum(0, n - 1, 0, 0, n - 1);
    if(ttSum >= n){
        return true;
    }
    return false;
}


int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    cin >> n >> p >> q;
    for(long long i = 0; i < n; ++i){
        cin >> a[i];
    }

    sort(a, a + n);

    long long l = 0;
    long long r = 1000000000;
    long long lc = -1;
    while(l <= r){
        long long mid = (l + r) / 2;
        bool ch = check(mid);
        if(ch){
            r = mid - 1;
            lc = mid;
        }else{
            l = mid + 1;
        }
    }

    cout << lc << "\n";
    return 0;
}

• Subtask 1: 0 / 50
• Subtask 2: 0 / 50