[20250319] BOJ / 골드1 / 가계부 / 이강현

lkhyun/202503/19 BOJ 골드1 가계부.md

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+```java
+import java.util.*;
+import java.io.*;
+
+public class Main {
+    static int N;
+    static int Q;
+    static long[] tree;
+    public static void main(String[] args) throws Exception {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        N = Integer.parseInt(st.nextToken());
+        Q = Integer.parseInt(st.nextToken());
+        tree = new long[N*4];
+        for(int i=0;i<Q;i++){
+            st = new StringTokenizer(br.readLine());
+            int option = Integer.parseInt(st.nextToken());
+            int arg1 = Integer.parseInt(st.nextToken());
+            long arg2 = Integer.parseInt(st.nextToken());
+            if(option == 1){ //수정
+                update(1,1,N,arg1,arg2);
+            }else if(option == 2){//구간 출력
+                bw.write(query(1,1,N,arg1,(int)arg2)+"\n");
+            }
+        }
+        bw.close();
+    }
+    public static void update(int cur, int start, int end, int idx, long diff){
+        if(idx<start || idx>end) return;
+        tree[cur] += diff;
+        if(start != end){
+            update(cur*2,start,(start+end)/2,idx,diff);
+            update(cur*2 + 1,(start+end)/2 + 1,end,idx,diff);
+        }
+    }
+    public static long query(int cur, int start, int end, int left, int right){
+        if(left>end || right<start) return 0;
+        if(left<=start && right>=end) return tree[cur];
+
+        long l = query(cur*2,start,(start+end)/2,left,right);
+        long r = query(cur*2+1,(start+end)/2 + 1, end,left,right);
+        return l+r;
+    }
+}
+```