Submission #199389

#	Time	Username	Problem	Language	Result	Execution time	Memory
199389		dimash241	Lamps (JOI19_lamps)	C++17	100 / 100	63 ms	43652 KiB

lamp

#pragma GCC target("avx2")
#pragma GCC optimize("O3")

# include <x86intrin.h>
# include <bits/stdc++.h>

# include <ext/pb_ds/assoc_container.hpp>
# include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;
using namespace std;
 
template<typename T> using ordered_set = tree <T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define _USE_MATH_DEFINES_
#define ll long long
#define ld long double
#define Accepted 0
#define pb push_back
#define mp make_pair
#define sz(x) (int)(x.size())
#define every(x) x.begin(),x.end()
#define F first
#define S second
#define lb lower_bound
#define ub upper_bound
#define For(i,x,y)  for (ll i = x; i <= y; i ++) 
#define FOr(i,x,y)  for (ll i = x; i >= y; i --)
#define SpeedForce ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
// ROAD to...                                                                                                                                                                                                                Red

inline void Input_Output () {
	//freopen(".in", "r", stdin);
   //freopen(".out", "w", stdout);
}

const double eps = 0.000001;
const ld pi = acos(-1);
const int maxn = 1e7 + 9;
const int mod = 1e9 + 7;
const ll MOD = 1e18 + 9;
const ll INF = 1e18 + 123;
const int inf = 2e9 + 11;
const int mxn = 1e6 + 9;
const int N = 6e5 + 123;                                          
const int M = 22;
const int pri = 997;
const int Magic = 2101;

const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, -1, 0, 1};
 
int n;
string s, t;
int dp[mxn][5][2];

int main () {
   	SpeedForce;
	cin >> n >> s >> t;
	for (int j = 0; j < 3; j ++)
		for (int k = 0; k < 2; ++k)
			dp[0][j][k] = inf;

	dp[0][0][0] = 0;
	for (int i = 0; i < n; ++i) {
		int x = s[i] - '0';
		int y = t[i] - '0';

		for (int j = 0; j < 3; ++j) {
			for (int k = 0; k < 2; ++k) {
				int &best = dp[i+1][j][k];
				best = inf;

				if (j == 0 && k != (x ^ y)) continue;
				if (j == 1 && k != y) continue;
				if (j == 2 && k == y) continue;

				for (int q = 0; q < 3; ++ q) {
					best = min(best, dp[i][q][0] + (q != j && j > 0) + k);
					best = min(best, dp[i][q][1] + (q != j && j > 0));
				}
			}
		}
		
		/*cout << "cs : " << i + 1 << '\n';
		for (int j = 0; j < 4; ++j) {
			if (dp[i+1][j] == inf) continue;
			cout << j << ' ' << dp[i+1][j] << '\n';
		}*/
	}
	int res = inf;
	for (int j = 0; j < 3; ++j)
		for (int k = 0; k < 2; ++k)
			res = min(res, dp[n][j][k]);
	cout << res << '\n';

   	return Accepted;
}

// B...a

• Subtask 1: 6 / 6
• Subtask 2: 41 / 41
• Subtask 3: 4 / 4
• Subtask 4: 49 / 49