Submission #1229888

#	Time	Username	Problem	Language	Result	Execution time	Memory
1229888		hainam2k9	Lamps (JOI19_lamps)	C++20	4 / 100	18 ms	6356 KiB

lamp

#include <bits/stdc++.h>
#define tt cin.tie(0), cout.tie(0), ios_base::sync_with_stdio(0)
#define fo freopen((NAME+".INP").c_str(), "r", stdin), freopen((NAME+".OUT").c_str(), "w", stdout)
#define ll long long
#define ull unsigned long long
#define i128 __int128
#define db long double
#define sz(a) ((int)(a).size())
#define pb emplace_back
#define pf emplace_front
#define pob pop_back
#define pof pop_front
#define lb lower_bound
#define ub upper_bound
#define fi first
#define se second
#define ins emplace
#define mp make_pair
using namespace std;
const int MOD = 1e9+7, MAXN = 1e6+5;
const string NAME = "";
int n,dp[MAXN],prefon=0,prefoff=0;
char a[MAXN],b[MAXN];
int main()
{
    tt;
    if(fopen((NAME + ".INP").c_str(), "r")) fo;
    cin >> n;
    for(int i = 1; i<=n; ++i)
        cin >> a[i];
    for(int i = 1; i<=n; ++i)
        cin >> b[i];
    memset(dp,0x3f,sizeof(dp));
    dp[0]=0;
    for(int i=1, j=0, MINoff=0, MINon=0; i<=n; ++i){
        if(b[i]=='0'&&b[i-1]!=b[i]) ++prefoff;
        if(b[i]=='1'&&b[i-1]!=b[i]) ++prefon;
        if(a[i]==b[i]) j=i, dp[i]=dp[i-1];
        else{
            dp[i]=dp[j]+1;
            if(b[i]=='0') dp[i]=min(dp[i],prefon+MINon+1);
            else dp[i]=min(dp[i],prefoff+MINoff+1);
        }
        if(b[i]=='0') MINoff=min(MINoff,dp[i]-prefoff+(a[i]=='0'&&a[i]+1=='0'));
        else MINon=min(MINon,dp[i]-prefon+(a[i]=='1'&&a[i+1]=='1'));
    }
    cout << dp[n];
}

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:3:19: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    3 | #define fo freopen((NAME+".INP").c_str(), "r", stdin), freopen((NAME+".OUT").c_str(), "w", stdout)
      |            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lamp.cpp:27:45: note: in expansion of macro 'fo'
   27 |     if(fopen((NAME + ".INP").c_str(), "r")) fo;
      |                                             ^~
lamp.cpp:3:63: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    3 | #define fo freopen((NAME+".INP").c_str(), "r", stdin), freopen((NAME+".OUT").c_str(), "w", stdout)
      |                                                        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
lamp.cpp:27:45: note: in expansion of macro 'fo'
   27 |     if(fopen((NAME + ".INP").c_str(), "r")) fo;
      |                                             ^~

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