Submission #600971

#	Time	Username	Problem	Language	Result	Execution time	Memory
600971		balbit	Shortcut (IOI16_shortcut)	C++14	100 / 100	1841 ms	82456 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], whoB[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;
        whoB[r] = -1;
    }
 
    int j = SZ(Bval)-1;
    if (M < 1e9 * 2+10) {
        REP(i,SZ(Aval)) {
            int a = Aval[i].s;
            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(vx,2)REP(vy,2) {
                int bval = whoB[vy]==a?sbigB[vy] : bigB[vy];
                MX(C[vx][vy], (cost-M+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;
        }
    }else{
        REP(i,SZ(Aval)) {
            int a = Aval[i].s;
            while (j>=0 && Aval[i].f+Bval[j].f > M) {
                int b = Bval[j].s;
                REP(vx,2) {
                    MX(bigB[vx], D[b] +(vx?-P[b]:P[b]));
                }
                --j;
            }
            REP(vx,2)REP(vy,2) {
                MX(C[vx][vy], (cost-M+D[a] + (vx?-P[a]:P[a]) + bigB[vy]));
            }
            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;
 
        // if (max(i00, i10) <= min(i01, i11)) {
        //     return 1;
        // }

        ll lb = max(C[0][0]-X, C[1][0] + X);
        ll rb = min(-C[0][1]+X, -C[1][1]-X);
        if (lb > rb) continue;
        int it = lower_bound(P, P+n, lb) - P;
        if (it < n && 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=P[n-1]/3, rb=P[n-1]+2e9+100;
 
    while (lb != rb) {
        ll M = (lb+rb)/2;
        if (okay(n,M,_c)) {
            rb = M;
        }else {
            lb = M+1;
        }
    }
 
    bug(lb);
    return lb;
}

Compilation message (stderr)

shortcut.cpp: In function 'bool okay(long long int, long long int, long long int)':
shortcut.cpp:106:12: warning: unused variable 'i00' [-Wunused-variable]
  106 |     signed i00=n, i01=-1, i10=0,i11=n-1;
      |            ^~~
shortcut.cpp:106:19: warning: unused variable 'i01' [-Wunused-variable]
  106 |     signed i00=n, i01=-1, i10=0,i11=n-1;
      |                   ^~~
shortcut.cpp:106:27: warning: unused variable 'i10' [-Wunused-variable]
  106 |     signed i00=n, i01=-1, i10=0,i11=n-1;
      |                           ^~~
shortcut.cpp:106:33: warning: unused variable 'i11' [-Wunused-variable]
  106 |     signed i00=n, i01=-1, i10=0,i11=n-1;
      |                                 ^~~

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