Submission #211170

#	Time	Username	Problem	Language	Result	Execution time	Memory
211170		amiratou	Lamps (JOI19_lamps)	C++14	100 / 100	49 ms	3612 KiB

lamp

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define rando mt19937 rng(chrono::steady_clock::now().time_since_epoch().count())
#define fi first
#define se second
#define debug(x) cerr << " - " << #x << ": " << x << endl;
#define debugs(x, y) cerr << " - " << #x << ": " << x << " " << #y << ": " << y << endl;
#define debugii(x) cerr << " - " << #x << ": " << x.fi<<","<<x.se << endl;
#define sep() cerr << "--------------------" << endl;
#define all(x) (x).begin(),(x).end()
#define sz(x) (ll)x.size()
#define ld long double
#define ll long long
//#define int ll
#define ii pair<int,int>
#define v vector<int>
#define vii vector<ii>
#define vv vector<vector<int> >
#define mp make_pair
#define INF 1000000000
#define pb push_back
#define EPS 1e-9
const int MOD = 1000000007; // 998244353
int dp[2][2][3],n;
string A,B;
char conv(char a,int t,int s){
	if(!s)a='0';
	if(s==1)a='1';
	if(t)a=(char)(1-(int)(a-'0')+'0');
	return a;
}
int32_t main(){
	boost;
	//freopen(".in","r",stdin);
	cin>>n>>A>>B;
	for (int i = 0; i < 2; ++i)
		for (int j = 0; j < 2; ++j)
			for (int z = 0; z < 3; ++z)
				dp[i][j][z]=INF;
	dp[0][0][2]=0;
	for (int idx = 0; idx < n; ++idx)
	{
		for (int t = 0; t < 2; ++t)
			for (int s = 0; s < 3; ++s)
				for (int i = 0; i < 2; ++i)
					for (int j = 0; j < 3; ++j)
					{
						int cost=0;
						cost+=(i?(i!=t):0)+((j!=2)?(j!=s):0);
						if(conv(A[idx],i,j)!=B[idx])continue;
						dp[(idx+1)&1][i][j]=min(dp[(idx+1)&1][i][j],dp[idx&1][t][s]+cost);
					}
		for (int j = 0; j < 2; ++j)
			for (int z = 0; z < 3; ++z)
				dp[idx&1][j][z]=INF;
	}
	int ans=INF;
	for (int i = 0; i < 2; ++i)
		for (int j = 0; j < 3; ++j)ans=min(ans,dp[n&1][i][j]);
	cout<<ans;
	return 0;
}
//long long
//array bounds
//special cases
//binary search

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