Submission #624069

#	Time	Username	Problem	Language	Result	Execution time	Memory
624069		Loki_Nguyen	Lamps (JOI19_lamps)	C++14	100 / 100	74 ms	16176 KiB

lamp

#include <bits/stdc++.h>
#define pll pair<ll, ll>
#define fi first
#define se second
#define pb push_back
#define task "tesddt"
#define pii pair<ll, pll>
using namespace std;
using ll = long long;
const int N = 1e6 + 2;
const ll mod = 998244353;
const ll base = 350;
const ll inf = 1e15;
int m, n, t, k, a[N], ans, dp[N][3];
void add(int& x, int y)
{
    if(x == -1 || x > y)x = y;
}
void sol()
{
    string A, B;
    cin >> n >> A >> B;
    memset(dp, -1, sizeof(dp));
    dp[0][0] = 0;
    ans = -1;
    for(int i = 0; i < n; i ++)
    {
        for(int l = 0; l < 3; l ++)
        {
            if(dp[i][l] == -1)continue;
            //cout << i <<" "<<l<<" "<<dp[i][l] << '\n';
            for(int r = 0; r < 3; r ++)
            {
                int cost = 0;
                if(l != r && r > 0)++cost;
                int vl, vr;
                if(r > 0)vr = r-1;
                else vr = A[i]-'0';
                if(vr != B[i]-'0')
                {
                    if(!i)++cost;
                    else 
                    {
                        if(l > 0)vl = l-1;
                        else vl = A[i-1]-'0';
                        if(vl == B[i-1]-'0')++cost;
                    }                    
                }
                //cout << r <<" "<<cost << '\n';
                add(dp[i+1][r], dp[i][l]+cost);
            }
        }
    }
    for(int i = 0; i < 3; i ++)if(dp[n][i] != -1)add(ans, dp[n][i]);
    cout << ans;
}
int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    if (fopen(task ".inp", "r"))
    {
        freopen(task ".inp", "r", stdin);
        freopen(task ".out", "w", stdout);
    }
    int ntest = 1;
    // cin >> ntest;
    while (ntest-- > 0)
        sol();
}

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:64:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |         freopen(task ".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
lamp.cpp:65:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |         freopen(task ".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

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