Submission #427241

#	Time	Username	Problem	Language	Result	Execution time	Memory
427241		cpp219	Lamps (JOI19_lamps)	C++14	100 / 100	214 ms	145200 KiB

lamp

#pragma GCC optimization "O2"
#pragma GCC optimization "unroll-loop"
#pragma GCC target ("avx2")

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define fs first
#define sc second
using namespace std;
const ll N = 1e6 + 9;
const ll inf = 1e9 + 7;
const ll Log2 = 20;
typedef pair<ll,ll> LL;

string s,p;
ll n,dp[N][3][2];

ll convert(ll now,ll zo,ll flip){
    if (zo == 1) now = 0;
    if (zo == 2) now = 1;
    if (flip) now = 1 - now;
    return now;
}

ll f(ll pos,ll zo,ll flip){
    if (pos > n) return 0;
    if (dp[pos][zo][flip] != -1) return dp[pos][zo][flip];
    ll now = s[pos] - '0',ans = inf;
    for (ll i = 0;i < 3;i++)
        for (ll j = 0;j < 2;j++){
            ll cur = convert(now,i,j),cost = 0;
            if (i && i != zo) cost++;
            if (j && j != flip) cost++;
            if (cur == p[pos] - '0') ans = min(ans,cost + f(pos + 1,i,j));
        }
    return dp[pos][zo][flip] = ans;
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    #define task "tst"
    if (fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        //freopen(task".out", "w", stdout);
    }
    cin>>n>>s>>p; s = " " + s; p = " " + p;
    memset(dp,-1,sizeof(dp));
    cout<<f(1,0,0);
}

Compilation message (stderr)

lamp.cpp:1: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    1 | #pragma GCC optimization "O2"
      | 
lamp.cpp:2: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    2 | #pragma GCC optimization "unroll-loop"
      | 
lamp.cpp: In function 'int main()':
lamp.cpp:45:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   45 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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