[20251001] BOJ / P5 / 지폐가 넘쳐흘러 / 권혁준

Author: oncsr

khj20006/202510/01 BOJ P5 지폐가 넘쳐흘러.md

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+```cpp
+#include <bits/stdc++.h>
+using namespace std;
+using ll = long long;
+
+int N, Q, LIMIT;
+ll w[262144]{}, l[524288]{}, r[524288]{}, x[524288]{};
+
+void init(int n) {
+    if(n >= LIMIT) return;
+    init(n*2); init(n*2+1);
+    l[n] = w[n] + max(l[n*2], r[n*2]);
+    r[n] = w[n] + max(l[n*2+1], r[n*2+1]);
+    x[n] = max({x[n*2], x[n*2+1], l[n] + r[n] - w[n]});
+}
+
+int main(){
+    cin.tie(0)->sync_with_stdio(0);
+
+    cin>>N;
+    for(int i=1;i<=N;i++) cin>>w[i];
+    LIMIT = N+1;
+    init(1);
+    cout<<x[1]<<'\n';
+    for(cin>>Q;Q--;) {
+        int i,d;
+        cin>>i>>d;
+        for(w[i]=d;i;i>>=1) {
+            l[i] = w[i] + max(l[i*2], r[i*2]);
+            r[i] = w[i] + max(l[i*2+1], r[i*2+1]);
+            x[i] = max({x[i*2], x[i*2+1], l[i] + r[i] - w[i]});
+        }
+        cout<<x[1]<<'\n';
+    }
+
+}
+```