baekjoon 20260112

code_study/Baekjoon/c/16724.c

@@ -0,0 +1,68 @@
+#include <stdio.h>
+
+char field[1001][1001];
+int N, M;
+int parent[1000000];
+int rank[1000000];
+
+int find(int x) {
+    if(x != parent[x]) return parent[x] = find(parent[x]);
+    return x;
+}
+
+void swap(int *a, int *b) {
+    int temp = *a;
+    *a = *b;
+    *b = temp;
+}
+
+void Union(int x, int y) {
+    x = find(x);
+    y = find(y);
+
+    if(rank[x] < rank[y]) swap(&x, &y);
+
+    parent[y] = x;
+
+    if(rank[x] == rank[y]) rank[x]++;
+}
+
+
+int area_num(int i, int j) {
+    return M*i + j;
+}
+
+int main() {
+    scanf("%d %d",&N, &M);
+    for(int i=0; i<N; i++) {
+        scanf("%s",field[i]);
+        for(int j=0; j<M; j++) {
+            int area = area_num(i, j);
+            parent[area] = area;
+        }
+    }
+
+    for(int i=0; i<N; i++) {
+        for(int j=0; j<M; j++) {
+            char arrow = field[i][j];
+            int now = area_num(i, j);
+            int next;
+
+            if(arrow == 'D') next = area_num(i+1, j);
+            else if(arrow == 'U') next = area_num(i-1,j);
+            else if(arrow == 'L') next = area_num(i,j-1);
+            else next = area_num(i,j+1);
+
+            Union(now, next);
+        }
+    }
+
+    int ans = 0;
+    for(int i=0; i<M*N; i++) {
+        if(i == parent[i]) ans++;
+    }
+
+    printf("%d\n",ans);
+
+    return 0;
+}

code_study/Baekjoon/c/16946.c

@@ -0,0 +1,111 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+int map[1000][1000];
+int group[1000][1000];
+int group_size[1000*1000];
+int N, M;
+bool visited[1000][1000];
+
+int group_num;
+int qu[1000*1000][2];
+int front, rear;
+int dx[4] = {-1, 1, 0, 0};
+int dy[4] = {0, 0, 1, -1};
+
+int result[1000][1000];
+
+bool isPossible(int x, int y) {
+    return (0<=x && x<M) && (0<=y && y<N) && map[y][x] == 0 && !visited[y][x];
+}
+
+void BFS(int x, int y) {
+    front = 0, rear = 0;
+    qu[rear][0] = x;
+    qu[rear++][1] = y;
+    visited[y][x] = true;
+    group[y][x] = group_num;
+    int cnt = 1;
+
+    while(front < rear) {
+        int cx = qu[front][0];
+        int cy = qu[front++][1];
+
+        for(int i=0; i<4; i++) {
+            int ny = cy + dy[i];
+            int nx = cx + dx[i];
+
+            if(isPossible(nx, ny)) {
+                qu[rear][0] = nx;
+                qu[rear++][1] = ny;
+                visited[ny][nx] = true;
+                group[ny][nx] = group_num;
+                cnt++;
+            }
+        }
+    }
+
+    group_size[group_num] = cnt;
+}
+
+int main() {
+    scanf("%d %d",&N, &M);
+    for(int i=0; i<N; i++) {
+        char line[10001];
+        scanf("%s", line);
+        for(int j=0; j<M; j++) {
+            map[i][j] = line[j] - '0';
+        }
+    }
+
+    for(int i=0; i<N; i++) {
+        for(int j=0; j<M; j++) {
+            if(map[i][j] == 0 && !visited[i][j]) {
+                BFS(j, i);
+                group_num++;
+            }
+        }
+    }
+
+    for(int y=0; y<N; y++) {
+        for(int x=0; x<M; x++) {
+            if(map[y][x] != 1) continue;
+
+            int cnt = 1;
+            int nearby_groups[4];
+            int nearby_idx = 0;
+
+            for(int i=0; i<4; i++) {
+                int nx = x + dx[i];
+                int ny = y + dy[i];
+
+                if(0<=nx && nx < M && 0<=ny && ny < N && map[ny][nx] == 0) {
+                    int current_group = group[ny][nx];
+
+                    bool group_checking = true;
+                    for(int i=0; i<nearby_idx; i++) {
+                        if(nearby_groups[i] == current_group) {
+                            group_checking = false;
+                        }
+                    }
+
+                    if(group_checking) {
+                        nearby_groups[nearby_idx++] = current_group;
+                        cnt += group_size[current_group];
+                    }
+                }
+            }
+
+            result[y][x] = cnt%10;
+        }
+    }
+
+    for(int i=0; i<N; i++) {
+        for(int j=0; j<M; j++) {
+            printf("%d",result[i][j]);
+        }
+        printf("\n");
+    }
+
+    return 0;
+}