更新

作业/刘航宇-day43/第一题/P2895.java

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+import java.util.*;
+import java.util.regex.*;
+
+public class P2895 {
+    static String normalize(String s) {
+        boolean neg = s.startsWith("-");
+        String t = neg ? s.substring(1) : s;
+        int i = 0;
+        while (i < t.length() - 1 && t.charAt(i) == '0') i++;
+        t = t.substring(i);
+        if (t.equals("0")) neg = false;
+        return neg ? ("-" + t) : t;
+    }
+
+    static int cmpNum(String a, String b) {
+        boolean na = a.startsWith("-");
+        boolean nb = b.startsWith("-");
+        if (na != nb) return na ? -1 : 1;
+        String aa = na ? a.substring(1) : a;
+        String bb = nb ? b.substring(1) : b;
+        if (!na) {
+            if (aa.length() != bb.length()) return aa.length() < bb.length() ? -1 : 1;
+            int c = aa.compareTo(bb);
+            return c < 0 ? -1 : (c > 0 ? 1 : 0);
+        } else {
+            if (aa.length() != bb.length()) return aa.length() > bb.length() ? -1 : 1;
+            int c = aa.compareTo(bb);
+            return c > 0 ? -1 : (c < 0 ? 1 : 0);
+        }
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        StringBuilder input = new StringBuilder();
+        while (in.hasNextLine()) {
+            if (input.length() > 0) input.append('\n');
+            input.append(in.nextLine());
+        }
+        Matcher m = Pattern.compile("-?\\d+").matcher(input.toString());
+        List<String> nums = new ArrayList<>();
+        while (m.find()) nums.add(normalize(m.group()));
+        nums.sort(P2895::cmpNum);
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < nums.size(); i++) {
+            if (i > 0) sb.append(',');
+            sb.append(nums.get(i));
+        }
+        System.out.println(sb.toString());
+        in.close();
+    }
+}

作业/刘航宇-day43/第三题/P2966.java

@@ -0,0 +1,27 @@
+import java.util.*;
+
+public class P2966 {
+    static long maxPrimeFactor(long n) {
+        if (n <= 1) return 1;
+        long max = -1;
+        while ((n & 1) == 0) { max = 2; n >>= 1; }
+        for (long i = 3; i * i <= n; i += 2) {
+            while (n % i == 0) { max = i; n /= i; }
+        }
+        if (n > 1) max = n;
+        return max;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        List<Long> nums = new ArrayList<>();
+        while (in.hasNextLong()) nums.add(in.nextLong());
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < nums.size(); i++) {
+            if (i > 0) sb.append(',');
+            sb.append(maxPrimeFactor(nums.get(i)));
+        }
+        System.out.println(sb.toString());
+        in.close();
+    }
+}

作业/刘航宇-day43/第二题/P2967.java

@@ -0,0 +1,36 @@
+import java.util.*;
+
+public class P2967 {
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        if (!in.hasNextLong()) { in.close(); return; }
+        long n = in.nextLong();
+        boolean neg = n < 0;
+        if (neg) n = -n;
+        StringBuilder sb = new StringBuilder();
+        if (neg) sb.append('-');
+        if (n == 1) {
+            sb.append('1');
+            System.out.println(sb.toString());
+            in.close();
+            return;
+        }
+        long p = 2;
+        boolean first = true;
+        while (n > 1 && p * p <= n) {
+            while (n % p == 0) {
+                if (!first) sb.append('*');
+                sb.append(p);
+                first = false;
+                n /= p;
+            }
+            p = (p == 2) ? 3 : (p + 2);
+        }
+        if (n > 1) {
+            if (!first) sb.append('*');
+            sb.append(n);
+        }
+        System.out.println(sb.toString());
+        in.close();
+    }
+}