50-9kyo-hwang

9-kyo-hwang/Brute Force/14500 테트로미노.cpp

@@ -0,0 +1,105 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+const vector<pair<int, int>> Offset{{-1, 0}, {0, 1}, {1, 0}, {0, -1}};
+
+int N, M;
+vector<vector<int>> Paper;
+vector<vector<bool>> Visited;
+
+bool OutOfBound(int x, int y)
+{
+    return x < 0 || x >= N || y < 0 || y >= M;
+}
+
+int Backtracking(int x, int y, int FigureCount = 1, int Sum = 0)
+{
+    if(OutOfBound(x, y) || Visited[x][y])
+    {
+        return 0;
+    }
+    else if(FigureCount > 4)
+    {
+        return Sum;
+    }
+    else
+    {
+        Visited[x][y] = true;
+        Sum += Paper[x][y];
+        int Answer = 0;
+
+        for(const auto& [dx, dy] : Offset)
+        {
+            Answer = max(Answer, Backtracking(x + dx, y + dy, FigureCount + 1, Sum));
+        }
+
+        Visited[x][y] = false;
+        Sum -= Paper[x][y];
+        return Answer;
+    }
+}
+
+int CalculateShapeT(int x, int y)
+{
+    int Sum = Paper[x][y];
+    int MinCell = 1001;
+    int SelectCnt = 1;
+    for(const auto& [dx, dy] : Offset)
+    {
+        int nx = x + dx, ny = y + dy;
+        if(OutOfBound(nx, ny))
+        {
+            continue;
+        }
+
+        MinCell = min(MinCell, Paper[nx][ny]);
+        Sum += Paper[nx][ny];
+        SelectCnt++;
+    }
+
+    if(SelectCnt < 4)  // is not Shape T
+    {
+        return 0;
+    }
+
+    if(SelectCnt == 5)  // Shape + -> Shape T
+    {
+        Sum -= MinCell;
+    }
+
+    return Sum;
+}
+
+int main()
+{
+    cin.tie(nullptr)->sync_with_stdio(false);
+
+    cin >> N >> M;
+    Paper.assign(N, vector(M, 0));
+    Visited.assign(N, vector(M, false));
+
+    for(auto& Row : Paper)
+    {
+        for(auto& Col : Row)
+        {
+            cin >> Col;
+        }
+    }
+
+    int Answer = 0;
+    for(int x = 0; x < N; ++x)
+    {
+        for(int y = 0; y < M; ++y)
+        {
+            Answer = max(Answer, Backtracking(x, y));  // except Shape T
+            Answer = max(Answer, CalculateShapeT(x, y));  // Shape T
+        }
+    }
+
+    cout << Answer;
+
+    return 0;
+}

9-kyo-hwang/Data Structure/21939 문제 추천 시스템 Version 1.cpp

@@ -0,0 +1,57 @@
+#include <iostream>
+#include <set>
+#include <unordered_map>
+
+using namespace std;
+
+int main()
+{
+    cin.tie(nullptr)->sync_with_stdio(false);
+
+    int N; cin >> N;
+    multiset<pair<int, int>> DB;
+    unordered_map<int, int> LevelMap;
+
+    for(int i = 0; i < N; ++i)
+    {
+        int P, L; cin >> P >> L;
+        DB.emplace(L, P);
+        LevelMap.emplace(P, L);
+    }
+
+    int M; cin >> M;
+    while(M--)
+    {
+        string Command; cin >> Command;
+        if(Command == "recommend")
+        {
+            int x; cin >> x;
+            if(x == 1)
+            {
+                const auto& [L, P] = *(--DB.end());
+                cout << P << "\n";
+            }
+            else if(x == -1)
+            {
+                const auto& [L, P] = *DB.begin();
+                cout << P << "\n";
+            }
+        }
+        else if(Command == "add")
+        {
+            int P, L; cin >> P >> L;
+            DB.emplace(L, P);
+            LevelMap.emplace(P, L);
+        }
+        else if(Command == "solved")
+        {
+            int P; cin >> P;
+            int L = LevelMap[P];
+
+            DB.erase(DB.find({L, P}));
+            LevelMap.erase(P);
+        }
+    }
+
+    return 0;
+}

9-kyo-hwang/Dynamic Programming/2240 자두나무.cpp

@@ -0,0 +1,55 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+using namespace std;
+
+int main()
+{
+    cin.tie(nullptr)->sync_with_stdio(false);
+
+    int T, W; cin >> T >> W;
+    vector<int> Poses(T + 1, 0);
+    for(int t = 1; t <= T; ++t)
+    {
+        cin >> Poses[t];
+        Poses[t] -= 1;
+    }
+
+    vector<vector<vector<int>>> DP(T + 1, vector(W + 1, vector(2, 0)));
+
+    for(int Walk = 0; Walk <= W; ++Walk)
+    {
+        for(int Time = 1; Time <= T; ++Time)
+        {
+            if(Time == 1)
+            {
+                DP[Time][Walk][0] = DP[Time - 1][Walk][0] + (Poses[Time] == 0);
+                if(Walk > 0)
+                {
+                    DP[Time][Walk][1] = DP[Time - 1][Walk - 1][0] + (Poses[Time] == 1);
+                }
+                continue;
+            }
+
+            if(Walk == 0)
+            {
+                DP[Time][Walk][0] = DP[Time - 1][Walk][0] + (Poses[Time] == 0);
+                DP[Time][Walk][1] = DP[Time - 1][Walk][1] + (Poses[Time] == 1);
+                continue;
+            }
+
+            DP[Time][Walk][0] = max(DP[Time - 1][Walk][0], DP[Time - 1][Walk - 1][1]) + (Poses[Time] == 0);
+            DP[Time][Walk][1] = max(DP[Time - 1][Walk - 1][0], DP[Time - 1][Walk][1]) + (Poses[Time] == 1);
+        }
+    }
+
+    int Ans = 0;
+    for(int Walk = 0; Walk <= W; ++Walk)
+    {
+        Ans = max({Ans, DP[T][Walk][0], DP[T][Walk][1]});
+    }
+    cout << Ans;
+
+    return 0;
+}

9-kyo-hwang/Graph Traversal/26146 즉흥 여행 (Easy).cpp

@@ -0,0 +1,52 @@
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+void DFSHelper(const vector<vector<int>>& Graph, vector<bool>& Visited, int SrcNode = 1)
+{
+    Visited[SrcNode] = true;
+    for(const auto& DstNode : Graph[SrcNode])
+    {
+        if(!Visited[DstNode])
+        {
+            DFSHelper(Graph, Visited, DstNode);
+        }
+    }
+}
+
+bool DFS(const int N, vector<vector<int>>& Graph)
+{
+    vector<bool> Visited(N + 1, false);
+    DFSHelper(Graph, Visited);
+
+    for(int Node = 1; Node <= N; ++Node)
+    {
+        if(!Visited[Node])
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
+int main()
+{
+    cin.tie(nullptr)->sync_with_stdio(false);
+
+    int N, M; cin >> N >> M;
+
+    vector<vector<int>> G(N + 1);
+    vector<vector<int>> GC(N + 1);
+
+    while(M--)
+    {
+        int v, w; cin >> v >> w;
+        G[v].emplace_back(w);
+        GC[w].emplace_back(v);
+    }
+
+    cout << (DFS(N, G) && DFS(N, GC) ? "Yes" : "No");
+
+    return 0;
+}

9-kyo-hwang/README.md

@@ -43,5 +43,11 @@
 | 40차시 | 2024.4.2   | Dynamic Programming        | [7579 앱](https://www.acmicpc.net/problem/7579)        | [#153](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/153) |
 | 41차시 | 2024.4.7   | Prefix Sum                 | [2015 수들의 합 4](https://www.acmicpc.net/problem/2015)        | [#155](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/155) |
 | 42차시 | 2024.4.29  | Minimum Spanning Tree(MST) | [17472 다리 만들기 2](https://www.acmicpc.net/problem/17472)    | [#159](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/159) |
-| 43차시 | 2024.4.28  | Data Structure             | [3015 오아시스 재결합](https://www.acmicpc.net/problem/3015)    | [#162](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/161) |
-| 44차시 | 2024.5.6   | Backtracking               | [6987 월드컵](https://www.acmicpc.net/problem/6987)    | [#164](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/161) |
+| 43차시 | 2024.4.28  | Data Structure             | [3015 오아시스 재결합](https://www.acmicpc.net/problem/3015)    | [#162](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/162) |
+| 44차시 | 2024.5.6   | Backtracking               | [6987 월드컵](https://www.acmicpc.net/problem/6987)    | [#164](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/164) |
+| 45차시 | 2024.5.9   | Dynamic Programming        | [2240 자두나무](https://www.acmicpc.net/problem/2240)    | [#166](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/166) |
+| 46차시 | 2024.5.13  | Simulation                 | [14503 로봇 청소기](https://www.acmicpc.net/problem/14503)    | [#167](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/167) |
+| 47차시 | 2024.5.16  | Brute Force                | [14500 테트로미노](https://www.acmicpc.net/problem/14503)    | [#171](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/171) |
+| 48차시 | 2024.5.20  | Shortest Path              | [1162 도로포장](https://www.acmicpc.net/problem/1162)    | [#175](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/175) |
+| 49차시 | 2024.5.23  | Data Structure             | [21939 문제 추천 시스템 Version 1](https://www.acmicpc.net/problem/21939)    | [#179](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/179) |
+| 50차시 | 2024.5.25  | Graph Traversal            | [26146 즉흥 여행 (Easy)](https://www.acmicpc.net/problem/26146)    | [#182](https://github.com/AlgoLeadMe/AlgoLeadMe-3/pull/182) |