#include <iostream> #include <vector> using namespace std; constexpr int INF = 1e9; vector <int> tab; inline int check(int mult) {// the first is up int ans = 0; vector <int> T = tab; for(int i = T.size() - 2; i >= 0; i--) { if(T[i] * mult - T[i + 1] * mult <= 0) { T[i] = INF * mult; ans++; } mult *= -1; } return ans; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); int n, ans = INF; cin >> n; for(int i = 0; i < n; i++) { int a; cin >> a; tab.push_back(a); } ans = check(-1); ans = min(ans, check(1)); tab.push_back(tab.back());//making the necessity to change the first element ans = min(ans, check(1)); ans = min(ans, check(-1)); cout << ans << "\n"; return 0; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | #include <iostream> #include <vector> using namespace std; constexpr int INF = 1e9; vector <int> tab; inline int check(int mult) {// the first is up int ans = 0; vector <int> T = tab; for(int i = T.size() - 2; i >= 0; i--) { if(T[i] * mult - T[i + 1] * mult <= 0) { T[i] = INF * mult; ans++; } mult *= -1; } return ans; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); int n, ans = INF; cin >> n; for(int i = 0; i < n; i++) { int a; cin >> a; tab.push_back(a); } ans = check(-1); ans = min(ans, check(1)); tab.push_back(tab.back());//making the necessity to change the first element ans = min(ans, check(1)); ans = min(ans, check(-1)); cout << ans << "\n"; return 0; } |