結果

問題 No.470 Inverse S+T Problem
ユーザー rogi52rogi52
提出日時 2021-08-15 06:38:44
言語 C++14
(gcc 12.3.0 + boost 1.83.0)
結果
WA  
実行時間 -
コード長 4,795 bytes
コンパイル時間 2,154 ms
コンパイル使用メモリ 195,992 KB
実行使用メモリ 6,948 KB
最終ジャッジ日時 2024-06-01 23:08:14
合計ジャッジ時間 3,175 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge3
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 2 ms
6,816 KB
testcase_01 AC 1 ms
6,940 KB
testcase_02 AC 2 ms
6,944 KB
testcase_03 WA -
testcase_04 AC 2 ms
6,944 KB
testcase_05 AC 2 ms
6,944 KB
testcase_06 AC 1 ms
6,944 KB
testcase_07 AC 2 ms
6,944 KB
testcase_08 AC 1 ms
6,944 KB
testcase_09 WA -
testcase_10 WA -
testcase_11 WA -
testcase_12 WA -
testcase_13 WA -
testcase_14 WA -
testcase_15 WA -
testcase_16 WA -
testcase_17 WA -
testcase_18 WA -
testcase_19 AC 1 ms
6,940 KB
testcase_20 WA -
testcase_21 AC 2 ms
6,944 KB
testcase_22 AC 2 ms
6,940 KB
testcase_23 AC 2 ms
6,944 KB
testcase_24 AC 2 ms
6,940 KB
testcase_25 WA -
testcase_26 AC 1 ms
6,940 KB
testcase_27 WA -
testcase_28 AC 2 ms
6,940 KB
testcase_29 AC 1 ms
6,944 KB
testcase_30 AC 2 ms
6,940 KB
権限があれば一括ダウンロードができます
コンパイルメッセージ
main.cpp: In function 'int main()':
main.cpp:126:51: warning: narrowing conversion of '(((int)(& U.std::vector<std::__cxx11::basic_string<char> >::operator[](((std::vector<std::__cxx11::basic_string<char> >::size_type)i)))->std::__cxx11::basic_string<char>::operator[](1)) + ((int)(& U.std::vector<std::__cxx11::basic_string<char> >::operator[](((std::vector<std::__cxx11::basic_string<char> >::size_type)i)))->std::__cxx11::basic_string<char>::operator[](2)))' from 'int' to 'char' [-Wnarrowing]
  126 |         si = string{U[i][0]}, ti = string{U[i][1] + U[i][2]};
main.cpp:126:51: warning: narrowing conversion of '(((int)(& U.std::vector<std::__cxx11::basic_string<char> >::operator[](((std::vector<std::__cxx11::basic_string<char> >::size_type)i)))->std::__cxx11::basic_string<char>::operator[](1)) + ((int)(& U.std::vector<std::__cxx11::basic_string<char> >::operator[](((std::vector<std::__cxx11::basic_string<char> >::size_type)i)))->std::__cxx11::basic_string<char>::operator[](2)))' from 'int' to 'char' [-Wnarrowing]
main.cpp:127:51: warning: narrowing conversion of '(((int)(& U.std::vector<std::__cxx11::basic_string<char> >::operator[](((std::vector<std::__cxx11::basic_string<char> >::size_type)j)))->std::__cxx11::basic_string<char>::operator[](1)) + ((int)(& U.std::vector<std::__cxx11::basic_string<char> >::operator[](((std::vector<std::__cxx11::basic_string<char> >::size_type)j)))->std::__cxx11::basic_string<char>::operator[](2)))' from 'int' to 'char' [-Wnarrowing]
  127 |         sj = string{U[j][0]}, tj = string{U[j][1] + U[j][2]};
main.cpp:127:51: warning: narrowing conversion of '(((int)(& U.std::vector<std::__cxx11::basic_string<char> >::operator[](((std::vector<std::__cxx11::basic_string<char> >::size_type)j)))->std::__cxx11::basic_string<char>::operator[](1)) + ((int)(& U.std::vector<std::__cxx11::basic_string<char> >::operator[](((std::vector<std::__cxx11::basic_string<char> >::size_type)j)))->std::__cxx11::basic_string<char>::operator[](2)))' from 'int' to '

ソースコード

diff # 

#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

struct scc_graph {
    int _n;
    struct edge {
        int to;
    };
    vector<pair<int,edge>> edges;

    template < class E > struct csr {
        vector<int> start;
        vector< E > elist;
        csr(int n, const vector<pair<int,E>> &edges)
            : start(n + 1), elist(edges.size()) {
                for(auto e : edges) start[e.first + 1]++;
                for(int i = 1; i <= n; i++) start[i] += start[i - 1];
                auto counter = start;
                for(auto e : edges) elist[counter[e.first]++] = e.second;
            }
    };

    scc_graph(int n) : _n(n) {}
    scc_graph() : _n(0) {}

    int num_vertices() { return _n; }

    void add_edge(int from, int to) {
        int n = num_vertices();
        assert(0 <= from && from < n);
        assert(0 <= to && to < n);
        edges.push_back({from, {to}});
    }

    // return pair of (# of scc, scc id)
    pair<int, vector<int>> scc_ids() {
        auto g = csr<edge>(_n, edges);
        int now_ord = 0, group_num = 0;
        vector<int> visited, low(_n), ord(_n, -1), ids(_n);
        visited.reserve(_n);
        auto dfs = [&](auto self, int v) -> void {
            low[v] = ord[v] = now_ord++;
            visited.push_back(v);
            for(int i = g.start[v]; i < g.start[v + 1]; i++){
                auto to = g.elist[i].to;
                if(ord[to] == -1){
                    self(self, to);
                    low[v] = min(low[v], low[to]);
                }else{
                    low[v] = min(low[v], ord[to]);
                }
            }
            if(low[v] == ord[v]){
                while(true){
                    int u = visited.back();
                    visited.pop_back();
                    ord[u] = _n;
                    ids[u] = group_num;
                    if(u == v) break;
                }
                group_num++;
            }
        };
        for(int i = 0; i < _n; i++) if(ord[i] == -1) dfs(dfs, i);
        for(auto &x : ids) x = group_num - 1 - x;
        return {group_num, ids};
    }

    vector<vector<int>> scc() {
        auto ids = scc_ids();
        int group_num = ids.first;
        vector<int> counts(group_num);
        for(auto x : ids.second) counts[x]++;
        vector<vector<int>> groups(ids.first);
        for(int i = 0; i < group_num; i++) groups[i].reserve(counts[i]);
        for(int i = 0; i < _n; i++) groups[ids.second[i]].push_back(i);
        return groups;
    }
};

struct two_sat {
    public:
        two_sat() : _n(0), scc(0) {}
        two_sat(int n) : _n(n), _answer(n), scc(2 * n) {}

        void add_clause(int i, bool f, int j, bool g) {
            assert(0 <= i && i < _n);
            assert(0 <= j && j < _n);
            scc.add_edge(2 * i + (f ? 0 : 1), 2 * j + (g ? 1 : 0));
            scc.add_edge(2 * j + (g ? 0 : 1), 2 * i + (f ? 1 : 0));
        }

        bool satisfiable() {
            auto id = scc.scc_ids().second;
            for(int i = 0; i < _n; i++){
                if(id[2 * i] == id[2 * i + 1]) return false;
                _answer[i] = id[2 * i] < id[2 * i + 1];
            }
            return true;
        }

        vector<bool> answer() { return _answer; }

    private:
        int _n;
        vector<bool> _answer;
        scc_graph scc;
};

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    
    int N; cin >> N;
    if(N >= 55){ cout << "Impossible" << endl; return 0; }

    vector<string> U(N);
    rep(i,N) cin >> U[i];

    two_sat ts(N);
    rep(i,N)rep(j,i){
        // U[i] <-> U[j]
        string si,ti,sj,tj;
        si = string{U[i][0]}, ti = string{U[i][1] + U[i][2]};
        sj = string{U[j][0]}, tj = string{U[j][1] + U[j][2]};
        if(si == sj || ti == tj) ts.add_clause(i, true, j, true);
        si = string{U[i][0] + U[i][1]}, ti = string{U[i][2]};
        sj = string{U[j][0]}, tj = string{U[j][1] + U[j][2]};
        if(si == tj && ti == sj) ts.add_clause(i, false, j, true);
        si = string{U[i][0]}, ti = string{U[i][1] + U[i][2]};
        sj = string{U[j][0] + U[j][1]}, tj = string{U[j][2]};
        if(si == tj && ti == sj) ts.add_clause(i, true, j, false);
        si = string{U[i][0] + U[i][1]}, ti = string{U[i][2]};
        sj = string{U[j][0] + U[j][1]}, tj = string{U[j][2]};
        if(si == sj || ti == tj) ts.add_clause(i, false, j, false);
    }

    if(!ts.satisfiable()){
        cout << "Impossible" << endl;
    }else{
        auto ans = ts.answer();
        rep(i,N){
            cout << U[i][0];
            if(!ans[i]){
                cout << " " << U[i][1];
            }else{
                cout << U[i][1] << " ";
            }
            cout << U[i][2] << endl;
        }
    }
}
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