Submission #671358

#	Time	Username	Problem	Language	Result	Execution time	Memory
671358		YENGOYAN	Rainforest Jumps (APIO21_jumps)	C++17	27 / 100	1139 ms	62128 KiB

jumps

#include "jumps.h"
#include <bits/stdc++.h>

using namespace std;

bool f = 1;
int n, s = 1;
vector<int> l, r, h;
vector<vector<int>> upmec, uppoqr;
vector<bool> used;
vector<pair<int, int>> seg;

void build(int l, int r, int u) {
    if (l == r) {
        if (l < n) seg[u] = { h[l], l };
        else seg[u] = { 2e9, l };
        return;
    }
    int m = (l + r) / 2;
    build(l, m, 2 * u + 1), build(m + 1, r, 2 * u + 2);
    seg[u] = min(seg[2 * u + 1], seg[2 * u + 2]);
}

pair<int, int> get(int l, int r, int lx, int rx, int u) {
    if (lx >= l && rx <= r) return seg[u];
    if (lx > r || rx < l) return { 2e9, -1 };
    int m = (lx + rx) / 2;
    return min(get(l, r, lx, m, 2 * u + 1), get(l, r, m + 1, rx, 2 * u + 2));
}

void calcDp(int u, vector<int> &dp, int c, int d){
    if(dp[u] != -1) return;
    if(u >= c && u <= d) {
        dp[u] = 0;
        return;
    }
    if(l[u] != -1 && r[u] != -1) {
        calcDp(l[u], dp, c, d);
        calcDp(r[u], dp, c, d);
        dp[u] = min(dp[l[u]], dp[r[u]]) + 1;
    }
    else if(l[u] != -1) {
        calcDp(l[u], dp, c, d);
        dp[u] = dp[l[u]] + 1;
    }
    else if(r[u] != -1){
        calcDp(r[u], dp, c, d);
        dp[u] = dp[r[u]] + 1;
    }
    else dp[u] = 1e9;
}

void calcUp(int u){
    if(used[u]) return;
    used[u] = 1;
    if(r[u] != -1 && l[u] != -1){
        if(h[r[u]] > h[l[u]]){
            calcUp(r[u]), calcUp(l[u]);
            upmec[u][0] = r[u];
            uppoqr[u][0] = l[u];
            for(int i = 1; i < 20; i++){
                if(upmec[u][i - 1] == -1) upmec[u][i] = -1;
                else upmec[u][i] = upmec[upmec[u][i - 1]][i - 1];
                if(uppoqr[u][i - 1] == -1) uppoqr[u][i] = -1;
                else uppoqr[u][i] = uppoqr[uppoqr[u][i - 1]][i - 1];
            }
        }
        else{
            calcUp(r[u]), calcUp(l[u]);
            upmec[u][0] = l[u];
            uppoqr[u][0] = r[u];
            for(int i = 1; i < 20; i++){
                if(upmec[u][i - 1] == -1) upmec[u][i] = -1;
                else upmec[u][i] = upmec[upmec[u][i - 1]][i - 1];
                if(uppoqr[u][i - 1] == -1) uppoqr[u][i] = -1;
                else uppoqr[u][i] = uppoqr[uppoqr[u][i - 1]][i - 1];
            }
        }
    }
    else if(r[u] != -1){
        calcUp(r[u]);
        upmec[u][0] = uppoqr[u][0] = r[u];
        for(int i = 1; i < 20; i++){
            if(upmec[u][i - 1] == -1) upmec[u][i] = uppoqr[u][i] = -1;
            else upmec[u][i] = uppoqr[u][i] = upmec[upmec[u][i - 1]][i - 1];
        }
    }
    else if(l[u] != -1){
        calcUp(l[u]);
        upmec[u][0] = uppoqr[u][0] = l[u];
        for(int i = 1; i < 20; i++){
            if(upmec[u][i - 1] == -1) upmec[u][i] = uppoqr[u][i] = -1;
            else upmec[u][i] = uppoqr[u][i] = upmec[upmec[u][i - 1]][i - 1];
        }
    }
    else {
        for(int i = 0; i < 20; i++) uppoqr[u][i] = upmec[u][i] = -1;
    }
}

void init(int N, vector<int> H) {
    n = N, h = H;
    l = r = vector<int> (n, -1);
    while(s < n) s <<= 1;
    seg.resize(2 * s);
    build(0, s - 1, 0);
    upmec = uppoqr = vector<vector<int>> (n, vector<int> (20));
    used = vector<bool> (n);
    for(int i = 0; i < n; i++) if(h[i] != i + 1) f = 0;
    if(f) return;
    stack<pair<int, int>> st;
    st.push({1e9, -1});
    for(int i = n - 1; i >= 0; i--){
        while(st.top().first < h[i]){
            st.pop();
        }
        r[i] = st.top().second;
        st.push({h[i], i});
    }
    while(st.size())st.pop();
    st.push({1e9, -1});
    for(int i = 0; i < n; i++){
        while(st.top().first < h[i]){
            st.pop();
        }
        l[i] = st.top().second;
        st.push({h[i], i});
    }
    for(int i = 0; i < n; i++) {
        if(!used[i]) calcUp(i);
    }
//     up[i][j]
}

int minimum_jumps(int A, int B, int C, int D) {
    if(f) return C - B;
    int ans = 0;
    if(C == D){
        pair<int, int> pp = get(A, B, 0, s - 1, 0);
        int node = pp.second;
        for(int i = 19; i >= 0; i--){
            if(upmec[node][i] == -1) continue;
            if(h[upmec[node][i]] <= h[C]){
                ans += (1 << i);
                node = upmec[node][i];
            }
        }
        for(int i = 19; i >= 0; i--){
            if(uppoqr[node][i] == -1) continue;
            if(h[uppoqr[node][i]] <= h[C]){
                ans += (1 << i);
                node = uppoqr[node][i];
            }
        }
        if(node == C) return ans;
        else return -1;
    }
    vector<int> dp(n, -1);
    for(int i = A; i <= B; i++) calcDp(i, dp, C, D);
    ans = 2e9;
    for(int i = A; i <= B; i++){
        ans = min(ans, dp[i]);
    }
    if (ans >= 1e9) return -1;
    return ans;
}

• Subtask 1: 4 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 13
• Subtask 4: 0 / 12
• Subtask 5: 23 / 23
• Subtask 6: 0 / 21
• Subtask 7: 0 / 19