Submission #968785

#	Time	Username	Problem	Language	Result	Execution time	Memory
968785		steveonalex	Rainforest Jumps (APIO21_jumps)	C++17	100 / 100	1228 ms	44396 KiB

jumps

#include <bits/stdc++.h>
#include "jumps.h"
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define ALL(v) (v).begin(), (v).end()
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
 
// mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng(1);
ll rngesus(ll l, ll r){return ((ull) rng()) % (r - l + 1) + l;}
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
 
ll LASTBIT(ll mask){return mask & (-mask);}
ll pop_cnt(ll mask){return __builtin_popcountll(mask);}
ll ctz(ll mask){return __builtin_ctzll(mask);}
ll clz(ll mask){return __builtin_clzll(mask);}
ll logOf(ll mask){return 63 - clz(mask);}
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b){a = b; return true;}
        return false;
    }
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b){a = b; return true;}
        return false;
    }
template <class T>
    void printArr(T& a, string separator = " ", string finish = "\n", ostream& out = cout){
        for(auto i: a) out << i << separator;
        out << finish;
    }
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

const int INF = 1e9;
struct SegmentTree{
    int n;
    vector<int> a;

    SegmentTree(){}
    SegmentTree(int _n){
        n = _n;
        a.resize(n * 2 + 2, -INF);
    }

    void update(int i, int v){
        i += n; if (!maximize(a[i], v)) return;
        while(i > 1){
            i >>= 1;
            a[i] = max(a[i * 2], a[i * 2 + 1]);
        }
    }

    int get(int l, int r){
        l += n; r += n + 1;
        int ans = -INF;
        while(l < r){
            if (l & 1) maximize(ans, a[l++]);
            if (r & 1) maximize(ans, a[--r]);
            l >>= 1; r >>= 1;
        }
        return ans;
    }
};
 
 
const int LOG_N = 18;
const int N = 2e5 + 69;
int n;
int h[N], pref[N], suff[N];
int nxt[LOG_N][N], lnxt[LOG_N][N];
SegmentTree segg;
map<int, int> pos;

void init(int _n, vector<int> H) {
    n = _n;
    for(int i = 0; i<n; ++i) h[i] = H[i];
 
    vector<int> st;
    for(int i = 0; i<n; ++i){
        while(st.size() && h[st.back()] <= h[i]) st.pop_back();
        if (st.empty()) pref[i] = n;
        else pref[i] = st.back();
        st.push_back(i);
    }
    st.clear();
    for(int i = n-1; i>=0; --i){
        while(st.size() && h[st.back()] <= h[i]) st.pop_back();
        if (st.empty()) suff[i] = n;
        else suff[i] = st.back();
        st.push_back(i);
    }
 
    for(int i = 0; i<n; ++i){
        if (h[pref[i]] > h[suff[i]]) nxt[0][i] = pref[i];
        else nxt[0][i] = suff[i];
        lnxt[0][i] = suff[i];
    }
    lnxt[0][n] = nxt[0][n] = n;
 
    for(int j = 1; j < LOG_N; ++j){
        for(int i = 0; i<=n; ++i){
            nxt[j][i] = nxt[j-1][nxt[j-1][i]];
            lnxt[j][i]= lnxt[j-1][lnxt[j-1][i]];
        }
    }

    segg = SegmentTree(n);
    for(int i = 0;i<n; ++i) segg.update(i + 1, H[i]);

    for(int i = 0; i<n; ++i) pos[H[i]] = i;
}

int walk_to_success(int x, int C, int D){
    int ans = 0;
    for(int j = LOG_N - 1; j>=0; --j){
        if (lnxt[j][x] < C) {
            x = lnxt[j][x];
            ans += MASK(j);
        }
    }
    x = lnxt[0][x];
    ans++;
    if (x > D) return INF;
    return ans;
}
 
int minimum_jumps(int A, int B, int C, int D) {

    int val_between = segg.get(B + 2, C);
    int val_r = segg.get(C + 1, D + 1);

    if (val_r < val_between) return -1;

    int R = val_r;
    int l = C, r = D;
    while(l < r){
        int mid = (l + r) >> 1;
        if (segg.get(C + 1, mid + 1) > val_between) r = mid;
        else l = mid + 1;
    }
    int L = h[l];

    l = A, r = B + 1;
    while(l < r){
        int mid = (l + r) >> 1;
        if (segg.get(mid+1, B+1) > R) l = mid + 1;
        else r = mid;
    }
    if (l > B) return -1;

    int val = segg.get(l + 1, B + 1);
    int x = pos[val];
    int ans = 0;
    for(int j = LOG_N - 1; j>=0; --j){
        if (nxt[j][x] == n) continue;
        if (h[nxt[j][x]] < L) {
            x = nxt[j][x]; 
            ans += MASK(j);
        }
    }

    ans += min(walk_to_success(x, C, D), walk_to_success(nxt[0][x], C, D) + 1);
    if (ans > INF) return -1;
 
    return ans;
}
 
 
// int main(void){
//     ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
 
//     int n; cin >> n;
//     vector<int> h(n);
//     for(int i = 0; i<n;++i) cin >> h[i];
 
//     init(n, h);
//     int q; cin >> q;
//     for(int i = 0; i<q; ++i){
//         int a, b, c, d; cin >> a >> b >> c >> d;
//         cout << minimum_jumps(a, b, c, d) << "\n";
//     }
 
//     return 0;
// }

• Subtask 1: 4 / 4
• Subtask 2: 8 / 8
• Subtask 3: 13 / 13
• Subtask 4: 12 / 12
• Subtask 5: 23 / 23
• Subtask 6: 21 / 21
• Subtask 7: 19 / 19