Submission #3589650

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Source Code Expand

#include <iostream>
#include <fstream>
#include <cmath>  
#include <cstdlib>
#include <ctime>
#include <algorithm>
#include <numeric>
#include <functional>
#include <string> 
#include <vector>
#include <bitset>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>

using namespace std;
using ll = long long;

template<class T> using V = vector<T>;
template<class T, class U> using P = pair<T, U>;

#define REP(i,n) for(int i = 0; i < int(n); i++)
#define FOR(i, m, n) for(int i = int(m);i < int(n);i++)
#define ALL(obj) (obj).begin(),(obj).end()

const ll MOD = (ll)1e9 + 7;
const ll HINF = (ll)1e18;
const ll LINF = (ll)1e9;
const long double PI = 3.1415926535897932384626433;

vector<int> dy = { 0,0,1,-1 };
vector<int> dx = { 1,-1,0,0 };

template<class T> void corner(bool flg, T hoge) {
	if (flg) {
		cout << hoge << endl;
		exit(0);
	}
	else return;
}

template <class T, class U>ostream &operator<<(ostream &o, const map<T, U>&obj) {
	o << "{"; for (auto &x : obj) o << " {" << x.first << " : " << x.second << "}" << ","; o << " }"; return o;
}

template <class T>ostream &operator<<(ostream &o, const set<T>&obj) {
	o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr) o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;
}

template <class T>ostream &operator<<(ostream &o, const vector<T>&obj) {
	o << "{"; for (int i = 0; i < (int)obj.size(); ++i)o << (i > 0 ? ", " : "") << obj[i]; o << "}"; return o;
}

template <class T, class U>ostream &operator<<(ostream &o, const pair<T, U>&obj) {
	o << "{" << obj.first << ", " << obj.second << "}"; return o;
}

template <template <class tmp>  class T, class U> ostream &operator<<(ostream &o, const T<U> &obj) {
	o << "{"; for (auto itr = obj.begin(); itr != obj.end(); ++itr)o << (itr != obj.begin() ? ", " : "") << *itr; o << "}"; return o;
}

void print(void) {
	cout << endl;
}

template <class Head> void print(Head&& head) {
	cout << head;
	print();
}

template <class Head, class... Tail> void print(Head&& head, Tail&&... tail) {
	cout << head << " ";
	print(forward<Tail>(tail)...);
}

void YN(bool flg) {
	cout << ((flg) ? "YES" : "NO") << endl;
}

void Yn(bool flg) {
	cout << ((flg) ? "Yes" : "No") << endl;
}

void yn(bool flg) {
	cout << ((flg) ? "yes" : "no") << endl;
}


int main() {
	string s; cin >> s;
	s = "." + s + ".";

	int N = s.size();

	V<V< int >> edge(N, V< int >(26, LINF));
	V<V<P<int, string>>> dp(N, V<P<int, string>>(26, { LINF,"" }));

	int idx;
	REP(i,26){
		char ch = char(int(i + 'a'));
		idx = N-1;
		for (int j = N-2; 0 <= j; --j) {
			edge[j][i] = idx;
			if (s[j] == ch)idx = j;
		}
	}

	REP(j, 26) dp[0][j] = { 0,"" };

	REP(i,N-1){
		int mini_cnt = LINF;
		string mini_str = "";
		REP(j, 26) {
			if ((dp[i][j].first < mini_cnt) || (dp[i][j].first == mini_cnt && dp[i][j].second < mini_str)) {
				mini_cnt = dp[i][j].first;
				mini_str = dp[i][j].second;
			}
		}
		
		REP(j,26){
			int cnt = mini_cnt + 1;
			char ch = char(int(j + 'a'));
			string str = mini_str;
			str.push_back(ch);
			int to = edge[i][j];
			if ((cnt < dp[to][j].first) || (cnt == dp[to][j].first && str < dp[to][j].second)) {
				dp[to][j].first = cnt;
				dp[to][j].second = str;
			}
		}
	}

	int ans_cnt = LINF;
	string ans_str = "";
	REP(j, 26) {
		if ((dp[N-1][j].first < ans_cnt) || (dp[N - 1][j].first == ans_cnt && dp[N - 1][j].second < ans_str)) {
			ans_cnt = dp[N - 1][j].first;
			ans_str = dp[N - 1][j].second;
		}
	}
	cout << ans_str << endl;
	return 0;
}

Submission Info

Judge Result