[김석찬 8주차 알고리즘 스터디]

김석찬/week8/17490(일감호에 다리넣기).cpp

@@ -0,0 +1,81 @@
+#include<iostream>
+#include<queue>
+#include<vector>
+#include<algorithm>
+
+using namespace std;
+
+int N, M, a, b, z, cnt;
+long long K;
+int parent[1000001];
+vector<vector<int>> arr;
+priority_queue<pair<int, pair<int, int>>, vector<pair<int, pair<int, int>>>, greater<>> Q;
+
+void reset() {
+    for (int i = 0; i <= N; i++) {
+        parent[i] = i;
+    }
+}
+
+int find(int x) {
+    if (parent[x] == x)return x;
+    else {
+        return parent[x] = find(parent[x]);
+    }
+}
+
+void Union(int x, int y) {
+    x = find(x);
+    y = find(y);
+    if (x == y)return;
+    parent[y] = x;
+}
+
+int main() {
+    ios::sync_with_stdio(false);
+    cin.tie(0);
+    cout.tie(0);
+    cin >> N >> M >> K;
+    reset();
+    arr.resize(N+1);
+    for (int i = 1; i <= N; i++) {
+        cin >> z;
+        Q.push({z, {0, i}});
+    }
+
+    for (int i = 0; i < M; i++) {
+        cin >> a >> b;
+        arr[a].emplace_back(b);
+        arr[b].emplace_back(a);
+    }
+
+    for (int i = 1; i <= N; i++) {
+        if (i == N)Q.push({0, {i, 1}});
+        else Q.push({0, {i, i + 1}});
+    }
+
+    while (!Q.empty()) {
+        int x = Q.top().second.first;
+        int y = Q.top().second.second;
+        int value = Q.top().first;
+        Q.pop();
+        auto it = find(arr[x].begin(), arr[x].end(), y);
+        auto it_1 = find(arr[y].begin(), arr[y].end(), x);
+        if (find(x) == find(y))continue;
+        if (it != arr[x].end() || it_1 != arr[y].end())continue;
+        Union(x, y);
+        cnt++;
+        K -= value;
+    }
+
+    if (M == 0 || M == 1) {
+        cout << "YES";
+    } else {
+        if (K >= 0 && cnt == N) {
+            cout << "YES";
+        } else {
+            cout << "NO";
+        }
+    }
+
+}

김석찬/week8/2151(거울 설치).cpp

@@ -0,0 +1,81 @@
+#include<iostream>
+#include<queue>
+#include<vector>
+
+using namespace std;
+
+int N;
+string arr[51];
+int visit[51][51][4];
+// 거울을 놓을수있는 형태는 2개 밖에 존재하지 않는다.
+vector<pair<int, int>> v;
+
+
+void input() {
+    cin >> N;
+    string s;
+    for (int i = 0; i < N; i++) {
+        cin >> s;
+        arr[i] = s;
+        for (int j = 0; j < s.length(); j++) {
+            if (s[j] == '#')v.emplace_back(j, i);
+        }
+    }
+}
+
+int xn[] = {0, 0, -1, 1};
+int yn[] = {-1, 1, 0, 0};
+// / 경우 : 위->왼, 왼->위, 하->우, 우->하
+// \ 경우 : 상->우, 우->상, 하->좌, 좌->하
+
+// 아래랑 왼쪽이 깐부, 위랑 오른쪽이 깐부
+int sol() {
+    priority_queue<pair<int, pair<int, pair<int, int>>>, vector<pair<int, pair<int, pair<int, int>>>>, greater<> > q;
+    for (int i = 0; i < 4; i++) {
+        q.push({0, {i, {v[0].first, v[0].second}}});
+    }
+    while (!q.empty()) {
+        int x = q.top().second.second.first;
+        int y = q.top().second.second.second;
+        int d = q.top().second.first;
+        int mirror = q.top().first;
+//        cout << "x : " << x << "/  y : " << y << "/  d : " << d << "/  mirror : " << mirror << '\n';
+        if (x == v[1].first && y == v[1].second)return mirror;
+        q.pop();
+        // 상하좌우 순서로 dis배열이 정의 되어있다.
+        int xx = x + xn[d];
+        int yy = y + yn[d];
+        if (yy < 0 || xx < 0 || yy >= N || xx >= N)continue;
+        if (arr[yy][xx] == '*')continue;
+        q.push({mirror, {d, {xx, yy}}});
+        visit[yy][xx][d] = true;
+
+        if (arr[yy][xx] == '!') { // 이경우에는 두가지의 방법이 가능함
+            if (d == 0 || d == 1) {
+                if (!visit[yy][xx][2]) {
+                    q.push({mirror + 1, {2, {xx, yy}}});
+                    visit[yy][xx][2] = true;
+                }
+                if (!visit[yy][xx][3]) {
+                    q.push({mirror + 1, {3, {xx, yy}}});
+                    visit[yy][xx][3] = true;
+                }
+            } else {
+                if (!visit[yy][xx][0]) {
+                    q.push({mirror + 1, {0, {xx, yy}}});
+                    visit[yy][xx][0] = true;
+                }
+                if (!visit[yy][xx][1]) {
+                    q.push({mirror + 1, {1, {xx, yy}}});
+                    visit[yy][xx][1] = true;
+                }
+            }
+        }
+
+    }
+}
+
+int main() {
+    input();
+    cout << sol();
+}