제출 #925160

#제출 시각아이디문제언어결과실행 시간메모리
925160TAhmed33밀림 점프 (APIO21_jumps)C++17
0 / 100
192 ms11552 KiB
#include <bits/stdc++.h> using namespace std; const int MAXN = 2e5 + 25; int a[MAXN], prv[MAXN], nxt[MAXN], n; int dp[MAXN][19], dp2[MAXN][19], dp3[MAXN][19]; void init (int N, vector <int> h) { n = N; for (int i = 0; i < n; i++) a[i + 1] = h[i]; stack <int> cur; cur.push(1); for (int i = 2; i <= n; i++) { while (!cur.empty() && a[i] > a[cur.top()]) { nxt[cur.top()] = i; cur.pop(); } cur.push(i); } while (!cur.empty()) { nxt[cur.top()] = 0; cur.pop(); } cur.push(n); for (int i = n - 1; i >= 1; i--) { while (!cur.empty() && a[i] > a[cur.top()]) { prv[cur.top()] = i; cur.pop(); } cur.push(i); } while (!cur.empty()) { prv[cur.top()] = 0; cur.pop(); } for (int i = 1; i <= n; i++) { dp2[0][i] = prv[i]; dp3[0][i] = nxt[i]; if (prv[i] && nxt[i] && a[prv[i]] > a[nxt[i]]) { dp[0][i] = prv[i]; } else if (prv[i] && nxt[i] && a[prv[i]] < a[nxt[i]]) { dp[0][i] = nxt[i]; } } for (int i = 1; i < 19; i++) { for (int j = 1; j <= n; j++) { dp2[i][j] = dp2[i - 1][dp2[i - 1][j]]; dp3[i][j] = dp3[i - 1][dp3[i - 1][j]]; dp[i][j] = dp[i - 1][dp[i - 1][j]]; } } } int jump (int a, int b) { for (int i = 18; i >= 0; i--) { if (b & (1 << i)) { a = dp[i][a]; } } return a; } int jump2 (int a, int b) { for (int i = 18; i >= 0; i--) { if (b & (1 << i)) { a = dp2[i][a]; } } return a; } int jump3 (int a, int b) { for (int i = 18; i >= 0; i--) { if (b & (1 << i)) { a = dp3[i][a]; } } return a; } int minimum_jumps (int a, int b, int c, int d) { a++; b++; c++; d++; int l = 0, r = n, ans = -1; while (l <= r) { int mid = (l + r) >> 1; int x = jump2(b, mid); if (x == 0 || x < a) { r = mid - 1; continue; } if (!nxt[x] || nxt[x] > d) { r = mid - 1; continue; } l = mid + 1; ans = mid; } if (ans == -1) return -1; int cur = jump2(b, ans); //cout << cur << '\n'; l = 1, r = n; int ans2 = 0; while (l <= r) { int mid = (l + r) >> 1; int x = jump(cur, mid); if (x == 0) { r = mid - 1; continue; } // cout << mid << " n\n"; if (x > c) { r = mid - 1; continue; } if (!nxt[x] || !prv[x] || nxt[x] > d) { r = mid - 1; continue; } l = mid + 1; ans2 = mid; } int cur2 = jump(cur, ans2); // cout << cur2 << '\n'; //cout << ans2 << '\n'; l = 0, r = n; int ans3 = -1; // cout << nxt[cur2] << '\n'; // cout << nxt[nxt[cur2]] << '\n'; // cout << nxt[nxt[nxt[cur2]]] << '\n'; while (l <= r) { int mid = (l + r) >> 1; int x = jump3(cur2, mid); // cout << x << " | " << mid << '\n'; if (!x || x >= c) { r = mid - 1; ans3 = mid; } else { l = mid + 1; } } //cout << ans3 << '\n'; if (ans3 == -1) return -1; int cur3 = jump3(cur2, ans3); if (!cur3) return -1; //cout << cur3 << '\n'; if (cur3 > d) return -1; return ans2 + ans3; }/* int main () { int n, q; cin >> n >> q; vector <int> h(n); for (auto &i : h) cin >> i; init(n, h); while (q--) { int a, b, c, d; cin >> a >> b >> c >> d; cout << minimum_jumps(a, b, c, d) << '\n'; } }*/
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