Submission #1286748

#	Time	Username	Problem	Language	Result	Execution time	Memory
1286748		trinm01	Lamps (JOI19_lamps)	C++20	4 / 100	23 ms	16216 KiB

lamp

// #pragma GCC optimize("O3")
// #pragma GCC optimization("Ofast,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
using namespace std;

#define int long long 
#define ll long long
#define FOR(i, l, r) for (int i = (l); i <= (r); i++)
#define FOD(i, r, l) for (int i = (r); i >= (l); i--)
#define fi first
#define se second
#define pii pair<int, int>

const ll mod = 1e9 + 7;
const int MAXN = 1e6 + 5;
const ll oo = 1e18 + 7;  
const int base = 10;

int n;
int a[MAXN], b[MAXN];

int solve(){
	int ans=0;
    for(int i=1; i<=n; ){
    	int j=i;
    	if(a[i]==b[i]){
	    	while(a[j]==b[j]){
	    		j++;	
	    	}
	    	i=j;
    	}
    	else{
    		ans++;
    		int j1=i;
    		while(b[j1]==b[i]){
    			j1++;
    		}
    		int j2=i;
    		while(a[j2]!=b[j2]){
    			j2++;
    		}
    		i=max(j1, j2);
    	}
    }
    return ans;
}

signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    
    // freopen("test.txt", "r", stdin);
    // freopen("o2.out", "w", stdout);

    if(fopen(".inp", "r")){
        freopen(".inp", "r", stdin);
        freopen(".out", "w", stdout);
    }

    cin >> n;
    FOR(i, 1, n){
    	char c;
    	cin >> c;
    	a[i]=(int)(c-'0');
    }
    FOR(i, 1, n){
    	char c;
    	cin >> c;
    	b[i]=(int)(c-'0');
    }
    
    int ans=oo;
    ans=solve();
    FOR(i, 1, n){
    	a[i]=1-a[i];
    }
    ans=min(ans, solve()+1);
    cout << ans;
    
    return 0;
}

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:59:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   59 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
lamp.cpp:60:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 41
• Subtask 3: 4 / 4
• Subtask 4: 0 / 49