Submission #718535

#TimeUsernameProblemLanguageResultExecution timeMemory
718535aryan12Rainforest Jumps (APIO21_jumps)C++17
4 / 100
1135 ms47292 KiB
#include "jumps.h" #include <bits/stdc++.h> #include <vector> using namespace std; const int MAXN = 2e5 + 5; int left_jump[19][MAXN], right_jump[18][MAXN], higher[19][MAXN]; vector<int> H; int N; void init(int n, std::vector<int> h) { stack<int> s; N = n; H.push_back(1e9); for(int i = 0; i < h.size(); i++) { H.push_back(h[i]); } H.push_back(1e9); N += 2; for(int i = 0; i < N; i++) { while(!s.empty() && H[s.top()] < H[i]) { s.pop(); } if(s.empty()) { left_jump[0][i] = i; } else { left_jump[0][i] = s.top(); } s.push(i); } while(!s.empty()) { s.pop(); } for(int i = N - 1; i >= 0; i--) { while(!s.empty() && H[s.top()] < H[i]) { s.pop(); } if(s.empty()) { right_jump[0][i] = i; } else { right_jump[0][i] = s.top(); } s.push(i); higher[0][i] = (H[right_jump[0][i]] >= H[left_jump[0][i]]) ? right_jump[0][i] : left_jump[0][i]; } for(int i = 1; i < 19; i++) { for(int j = 0; j < N; j++) { left_jump[i][j] = left_jump[i - 1][left_jump[i - 1][j]]; right_jump[i][j] = right_jump[i - 1][right_jump[i - 1][j]]; higher[i][j] = higher[i - 1][higher[i - 1][j]]; } } } int max_height(int l, int r) { int cur = l; for(int i = 18; i >= 0; i--) { if(right_jump[i][cur] <= r) { cur = right_jump[i][cur]; } } return cur; } int minimum_jumps(int A, int B, int C, int D) { A++, B++, C++, D++; if(B == C - 1) { // no middle stuff return (right_jump[0][B] <= D) ? 1 : -1; } int middle_tallest_index = max_height(B + 1, C - 1); if(H[B] > H[middle_tallest_index]) { return (right_jump[0][B] <= D) ? 1 : -1; } int current = B; for(int i = 18; i >= 0; i--) { if(A <= left_jump[i][current] && H[left_jump[i][current]] <= H[middle_tallest_index]) { current = left_jump[i][current]; } } int ans = 0; if(A <= left_jump[0][current]) { if(right_jump[0][left_jump[0][current]] <= D) { return 1; } } else { for(int i = 18; i >= 0; i--) { if(H[higher[i][current]] <= H[middle_tallest_index]) { ans += (1 << i); current = higher[i][current]; } } if(current == middle_tallest_index) { return (right_jump[0][current] <= D) ? ans + 1 : -1; } if(left_jump[0][current] > 0 && right_jump[0][left_jump[0][current]] <= D) { return ans + 2; } } for(int i = 18; i >= 0; i--) { if(right_jump[i][current] < C) { ans += (1 << i); current = right_jump[i][current]; } } ans++; current = right_jump[0][current]; return (C <= current && current <= D) ? ans : -1; }

Compilation message (stderr)

jumps.cpp: In function 'void init(int, std::vector<int>)':
jumps.cpp:17:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |     for(int i = 0; i < h.size(); i++)
      |                    ~~^~~~~~~~~~
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