Submission #384784

#	Time	Username	Problem	Language	Result	Execution time	Memory
384784		ACmachine	Lamps (JOI19_lamps)	C++17	4 / 100	39 ms	18724 KiB

lamp

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;

template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using ordered_map = tree<T, U, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long ll;
typedef long double ld;

typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

typedef vector<int> vi;
typedef vector<ll> vll;

#define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
#define FORD(i,j,k,in) for(int i=(j); i >=(k);i-=in)
#define REP(i,b) FOR(i,0,b,1)
#define REPD(i,b) FORD(i,b,0,1)
#define pb push_back
#define mp make_pair
#define ff first
#define ss second
#define all(x) begin(x), end(x)
#define MANY_TESTS int tcase; cin >> tcase; while(tcase--)

const double EPS = 1e-9;
const int MOD = 1e9+7;
const ll INFF = 1e18;
const int INF = 1e9;
const ld PI = acos((ld)-1);
const vi dy = {1, 0, -1, 0, -1, 1, 1, -1};
const vi dx = {0, 1, 0, -1, -1, 1, -1, 1};

void DBG(){cout << "]" << endl;}
template<typename T, typename ...U> void DBG(const T& head, const U... args){ cout << head << "; "; DBG(args...); }
#define dbg(...) cout << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__);
#define chk() cout << "Check at line(" << __LINE__ << ") hit." << endl;

template<class T, unsigned int U>
ostream& operator<<(ostream& out, const array<T, U> &v){out << "[";  REP(i, U) out << v[i] << ", ";  out << "]"; return out;}
template <class T, class U>
ostream& operator<<(ostream& out, const pair<T, U> &par) {out << "[" << par.first << ";" << par.second << "]"; return out;}
template <class T>
ostream& operator<<(ostream& out, const set<T> &cont) { out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template <class T, class U>
ostream& operator<<(ostream& out, const map<T, U> &cont) {out << "{"; for( const auto &x:cont) out << x << ", "; out << "}"; return out; }
template<class T>
ostream& operator<<(ostream& out, const vector<T> &v){ out << "[";  REP(i, v.size()) out << v[i] << ", ";  out << "]"; return out;}

template<class T>
istream& operator>>(istream& in, vector<T> &v){ for(auto &x : v) in >> x; return in; }

int main(){
 	ios_base::sync_with_stdio(false);
 	cin.tie(NULL); cout.tie(NULL);
 	int n; cin >> n;
    string a, b;
    cin >> a >> b;
    vector<array<int, 2>> seg;
    REP(i, b.length()){
        if(i == 0 || b[i] != b[i - 1])
            seg.pb({i, i});
        else
            seg.back()[1]++;
    }
    int m = seg.size();
    array<int, 2> nl = {INF, INF};
    vector<array<int, 2>> dp(m + 1, nl);
    dp[0][0] = 0; dp[0][1] = 1;
    REP(i, m){
        bool all_correct = true;
        bool all_reversed = true;
        bool pos_change = false; //reversed + good -> here I want to end open toggle
        bool pos_change2 = false; // good + reversed; -> here I want to start new open toggle
        int pref_eq = 0;
        int suf_eq = 0;
        int pref_rev = 0;
        int suf_rev = 0;
        FOR(j, seg[i][0], seg[i][1] + 1, 1){
            if(a[j] == b[j])
                all_reversed = false;
            if(a[j] != b[j])
                all_correct = false;
        }
        FOR(j, seg[i][0], seg[i][1] + 1, 1){
            if(a[j] == b[j])
                pref_eq++;
            else break;
        }
        FOR(j, seg[i][0], seg[i][1] + 1, 1){
            if(a[j] != b[j])
                pref_rev++;
            else break;
        }
        FORD(j, seg[i][1], seg[i][0], 1){
            if(a[j] == b[j])
                suf_eq++;
            else break;
        }
        FORD(j, seg[i][1], seg[i][0], 1){
            if(a[j] != b[j])
                suf_rev++;
            else break;
        }
        if(pref_rev + suf_eq == (seg[i][1] + 1 - seg[i][0]))
            pos_change = true;
        if(pref_eq + suf_rev == (seg[i][1] + 1 - seg[i][0]))
            pos_change2 = true;
        // special transitions
        if(all_correct){
            dp[i + 1][0] = min(dp[i + 1][0], min(dp[i][0], dp[i][1]));
        }
        if(all_reversed){
            dp[i + 1][1] = min(dp[i + 1][1], min(dp[i][1], dp[i][0] + 1));
        }
        if(pos_change){
            dp[i + 1][0] = min(dp[i + 1][0], min(dp[i][0] + 1, dp[i][1]));
        }
        if(pos_change2){
            dp[i + 1][1] = min(dp[i + 1][1], min(dp[i][0] + 1, dp[i][1] + 1));
        }
        // general transitions
        dp[i + 1][0] = min(dp[i + 1][0], min(dp[i][0] + 1, dp[i][1] + 1));
        dp[i + 1][1] = min(dp[i + 1][1], min(dp[i][0] + 2, dp[i][1] + 1));
        dp[i + 1][1] = min(dp[i + 1][1], dp[i + 1][0] + 1);
        dp[i + 1][0] = min(dp[i + 1][0], dp[i + 1][1]);
    }
    cout << min(dp[m][0], dp[m][1]) << "\n";
    return 0;
}

Compilation message (stderr)

lamp.cpp: In function 'int main()':
lamp.cpp:19:40: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   19 | #define FOR(i,j,k,in) for(int i=(j); i < (k);i+=in)
      |                                        ^
lamp.cpp:21:18: note: in expansion of macro 'FOR'
   21 | #define REP(i,b) FOR(i,0,b,1)
      |                  ^~~
lamp.cpp:64:5: note: in expansion of macro 'REP'
   64 |     REP(i, b.length()){
      |     ^~~

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