Submission #600842

#	Time	Username	Problem	Language	Result	Execution time	Memory
600842		balbit	Shortcut (IOI16_shortcut)	C++14	0 / 100	1 ms	212 KiB

shortcut

// 我的心裡只有你沒有他
#pragma GCC optimize("O3", "unroll-loops")
#include "shortcut.h"

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

#define ll long long
#define int ll
#define pii pair <int, int >
#define f first
#define s second

#define MX(a,b) a = max(a,b)
#define MN(a,b) a = min(a,b)

#define ALL(x) (x).begin(), (x).end()
#define SZ(x) (int)((x).size())

#ifdef BALBIT
#define bug(...) cerr<<"#"<<__LINE__<<": "<<#__VA_ARGS__<<"- ", _do(__VA_ARGS__)
template<typename T> void _do(T && x) {cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T && x, S && ...y) {cerr<<x<<", "; _do(y...);}
#else
#define bug(...)
#endif // BALBIT


#define pb push_back
#define REP(i,n) for (int i = 0; i<(n); ++i)
#define REP1(i,n) for (int i = 1; i<=(n); ++i)


const int maxn = 1e6+5;
const ll inf = 0x3f3f3f3f3f3f3f3f;

int P[maxn], D[maxn]; // position, depth

vector<pii> Aval, Bval; // A is Da + Pa, B is Db - Pb

ll C[2][2], bigB[2], sbigB[2];

bool okay(int n, ll M, ll cost) {
    // for all D[a] + P[a] - D[b] + P[b] >= M, 

    bug(M, cost);
    
    REP(r,2) REP(R, 2) {
        C[r][R] = -inf;
        bigB[r] = sbigB[r] = -inf;
    }

    int j = SZ(Bval)-1;
    REP(i,SZ(Aval)) {
        int a = Aval[i].s;
        ll meme = D[a] * 2;
        while (j>=0 && Aval[i].f+Bval[j].f > M) {
            // work j
            int b = Bval[j].s;
            bug(a,b,Aval[i].f + Bval[i].f);
            REP(vx,2) {
                ll val = D[b] + (vx?-1:1)*P[b];
                if (val > bigB[vx]) {
                    sbigB[vx] = bigB[vx];
                    // whoB[vx] = b;
                    bigB[vx] = val;
                }else if (val > sbigB[vx]) {
                    sbigB[vx] = val;
                }
            }
            --j;
        }

        REP(vy,2) {
            int bval = bigB[vy]==meme?sbigB[vy] : bigB[vy];
            REP(vx, 2) {
                MX(C[vx][vy], (D[a] + (vx?-1:1)*P[a] + bval));
            }
        }

        if (C[0][0] > -C[1][1]) return 0;
        if (C[0][1] > -C[1][0]) return 0;
    }

    REP(X,2) REP(Y,2) C[X][Y] += cost-M;

    bug(C[0][0], C[0][1], C[1][0], C[1][1]);

    vector<ll> ya; 

    signed i00=n, i01=-1, i10=0,i11=n-1;

    REP(a, n) {
        ll X = P[a];

        while (i00-1>=0 && P[i00-1] >= C[0][0]-X) --i00;
        while (i10<n && P[i10] < C[1][0] + X) ++i10;
        while (i01+1 <n && P[i01+1] <= -C[0][1] + X) ++i01;
        while (i11 >= 0 && P[i11] > -C[1][1] - X) --i11;

        // ll lb = max(C[0][0]-X, C[1][0] + X);
        // ll rb = min(-C[0][1]+X, -C[1][1]-X);
        // bug(X, lb, rb);
        // if (lb > rb) continue;
        // ya.pb({lb, 0});
        // ya.pb({rb, -1});

        if (max(i00, i10) <= min(i01, i11)) {
            return 1;
        }

        // int it = lower_bound(P, P+n, lb) - P;
        // if (it < n && P[it]>=lb && P[it] <= rb) {
        //     return 1;
        // }
    }

    return 0;

    // conditions: Pa + Da + 


}

long long find_shortcut(signed n, std::vector<signed> l, std::vector<signed> _d, signed _c)
{
    // watermelon 4A orz
    bug(1,2);
    P[0] = 0;
    REP(i,n-1) P[i+1] = P[i] + l[i];
    // P[n] = inf*2;
    REP(i,n) D[i] = _d[i];

    REP(i,n) {
        Aval.pb({D[i] + P[i], i});
        Bval.pb({D[i] - P[i], i});
    }

    sort(ALL(Aval));
    sort(ALL(Bval));

    int lb=0, rb=1e15;

    while (lb != rb) {
        ll M = (lb+rb)/2;
        if (okay(n,M,_c)) {
            rb = M;
        }else {
            lb = M+1;
        }
    }

    bug(lb);
    return lb;
}

/*


4 10
10 20 20
0 40 0 30


9 30
10 10 10 10 10 10 10 10
20 0 30 0 0 40 0 40 0

3 10
1 1
0 1000 0

*/

//
//signed main(){
////    ll hi = find_shortcut(9, {10, 10, 10, 10, 10, 10, 10, 10},
////{20, 0, 30, 0, 0, 40, 0, 40, 0}, 30);
////    bug(hi);
//    int n; cin>>n;
//    REP(www, 100) {
//        vector<int> l, d;
//        REP(i,n-1) {
//            l.pb(rand()%1000000);
//        }
//        REP(i,n) {
//            d.pb(rand()%1000000);
//        }
//        bug(find_shortcut(n, l, d, 1));
//    }
//}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 14
• Subtask 3: 0 / 8
• Subtask 4: 0 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3