[20250311] BOJ / P5 / 마법의 구슬 / 권혁준

khj20006/202503/11 BOJ P5 마법의 구슬.md

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+```java
+
+import java.util.*;
+import java.io.*;
+
+class SegTree{
+	int[] tree;
+	SegTree(int size){
+		tree = new int[size*4 + 1];
+	}
+	void upt(int s, int e, int i, int n) {
+		if(s == e) {
+			tree[n]++;
+			return;
+		}
+		int m=(s+e)>>1;
+		if(i<=m) upt(s,m,i,n*2);
+		else upt(m+1,e,i,n*2+1);
+		tree[n] = tree[n*2] + tree[n*2+1];
+	}
+	int find(int s, int e, int l, int r, int n) {
+		if(l>r || l>e || r<s) return 0;
+		if(l<=s && e<=r) return tree[n];
+		int m=(s+e)>>1;
+		return find(s,m,l,r,n*2) + find(m+1,e,l,r,n*2+1);
+	}
+}
+
+class Main {
+
+	// IO field
+	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+	static BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
+	static StringTokenizer st;
+
+	static void nextLine() throws Exception {st = new StringTokenizer(br.readLine());}
+	static int nextInt() {return Integer.parseInt(st.nextToken());}
+	static long nextLong() {return Long.parseLong(st.nextToken());}
+	static void bwEnd() throws Exception {bw.flush();bw.close();}
+
+	// Additional field
+
+	static long S, F, M;
+	static long[] C;
+	static boolean[] sieve;
+
+	public static void main(String[] args) throws Exception {
+
+		ready();
+		solve();
+
+		bwEnd();
+
+	}
+
+	static void ready() throws Exception{
+
+		nextLine();
+		S = nextLong();
+		F = nextLong();
+		M = nextLong();
+		F += S;
+		sieve = new boolean[(int)M+1];
+		C = new long[(int)M+1];
+
+	}
+
+	static void solve() throws Exception{
+
+		for(int i=2;i*i<=M;i++) if(!sieve[i]) for(int j=i*i;j<=M;j+=i) sieve[j] = true;
+
+		for(int i=2;i<=M;i++) if(!sieve[i]) for(long j=i;j<=F;j*=i) C[i] += F/j;
+		for(int i=2;i<=M;i++) if(!sieve[i]) for(long j=i;j<=S;j*=i) C[i] -= S/j;
+		for(int i=2;i<=M;i++) if(!sieve[i]) for(long j=i;j<=F-S;j*=i) C[i] -= (F-S)/j;
+
+		int ans = 1;
+		for(int i=2;i<=M;i++) {
+			if(!sieve[i]) {
+				if(C[i] > 0) ans = i;
+				continue;
+			}
+			int temp = i, cnt = 0;
+			boolean can = true;
+			for(int j=2;j*j<=temp;j++) if(!sieve[j] && temp%j == 0) {
+				cnt = 0;
+				while(temp%j == 0) {
+					temp/=j;
+					cnt++;
+				}
+				can &= C[j] >= cnt;
+				cnt = 0;
+			}
+			if(temp != 1) can &= C[temp] >= 1;
+			if(can) ans = i;
+		}
+		bw.write(ans + "\n");
+
+	}
+
+}
+
+```