baekjoon 20260308

code_study/Baekjoon/c/2533.c

@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <stdbool.h>
+
+#define MAX_N 1000000
+
+int dp[MAX_N + 1][2];
+bool visited[MAX_N + 1];
+
+int head[MAX_N + 1];
+int to[MAX_N * 2 + 1];
+int next[MAX_N * 2 + 1];
+int edge_cnt = 0;
+
+void add_edge(int u, int v) {
+    edge_cnt++;
+    to[edge_cnt] = v;
+    next[edge_cnt] = head[u];
+    head[u] = edge_cnt;
+}
+
+int min(int a, int b) {
+    return a < b ? a : b;
+}
+
+void find(int node) {
+    visited[node] = true;
+    dp[node][1] = 1;
+
+    for(int e = head[node]; e != 0; e = next[e]) {
+        int child = to[e];
+
+        if(visited[child]) continue;
+        
+        find(child);
+        dp[node][1] += min(dp[child][1], dp[child][0]);
+        dp[node][0] += dp[child][1];
+    }
+}
+
+int main() {
+    int N;
+    if(scanf("%d", &N) != 1) return 0;
+
+    for(int i = 0; i < N - 1; i++) {
+        int u, v;
+        scanf("%d %d", &u, &v);
+        add_edge(u, v);
+        add_edge(v, u);
+    }
+
+    find(1);
+
+    printf("%d\n", min(dp[1][0], dp[1][1]));
+
+    return 0;
+}