#interviewstreet

import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.ArrayList; import java.util.List; public class Solution { private static final int MOD = 1000007; private boolean[] isPrime; private int[] multiplier; private List<Integer> prime; public static void main(String[] args) throws Exception { Solution main = new Solution(); main.run(); System.exit(0); } public void run() throws Exception { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); int N = Integer.parseInt(br.readLine()); isPrime = new boolean[N + 1]; multiplier = new int[N + 1]; prime = new ArrayList<Integer>(); generatePrime(N); // for (int i = 0; i <= N; i++) // System.out.println("" + i + ", " + isPrime[i]); generateMultiplier(N); long sum = 1L; for (int i = 1; i <= N; i++) if (multiplier[i] != 0) { sum *= (long) (2 * multiplier[i] + 1) % MOD; sum %= MOD; } System.out.println(sum); } public void generatePrime(int N) { for (int i = 2; i <= N; i++) if (isPrime[i] == false) { prime.add(i); for (int j = 2; j * i <= N; j++) isPrime[i * j] = true; } } public void generateMultiplier(int N) { // int left = 1; // for (int i = 1; i <= N; i++) { // left *= i; // for (int j : prime) { // while (left % j == 0) { // multiplier[j]++; // left /= j; // } // if (left < j) // It helps prune and save the time. // break; // } // } for (int j : prime) { int cpy = N; int e = 0; while (cpy != 0) { e += cpy / j; cpy /= j; } multiplier[j] = e; } } public boolean check(int x, int N) { return true; } }

import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.Arrays; /** * */ /** * @author antonio081014 * @time Oct 6, 2012, 11:57:39 PM */ public class Solution { public static void main(String[] args) throws Exception { Solution main = new Solution(); main.run(); System.exit(0); } public void run() throws Exception { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); String[] str = br.readLine().split("\\s"); int N = Integer.parseInt(str[0]); int K = Integer.parseInt(str[1]); str = br.readLine().split("\\s"); int[] cost = new int[N]; for (int i = 0; i < N; i++) { cost[i] = Integer.parseInt(str[i]); } Arrays.sort(cost); int total = 0; int _K, i; for (i = N - 1, _K = K; i >= 0 && _K > 0; i--, _K--) { total += cost[i]; } int index = 0; int round = 1; for (; i >= 0; i--) { total += cost[i] * (round + 1); index++; if (index >= K) { round++; index = 0; } } System.out.println(total); } }

import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.Arrays; /** * */ /** * @author antonio081014 * @time: Oct 6, 2012, 2:32:58 PM */ public class Solution { private int K; /** * @param args */ public static void main(String[] args) throws Exception { Solution main = new Solution(); main.run(); System.exit(0); } public void run() throws Exception { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); String[] str = br.readLine().split("\\s"); int N = Integer.parseInt(str[0]); K = Integer.parseInt(str[1]); int[] array = new int[N]; str = br.readLine().split("\\s"); for (int i = 0; i < N; i++) array[i] = Integer.parseInt(str[i]); Arrays.sort(array); int count = 0; for (int i = 0; i < N; i++) { count += binaryLeft(0, i - 1, array, i); count += binaryRight(i + 1, N - 1, array, i); } System.out.println(count / 2); } private int binaryLeft(int low, int high, int[] array, int index) { while (low <= high) { int mid = (low + high) / 2; if (array[mid] + K == array[index]) { // System.out.println("" + array[index] + " " + array[mid]); return 1; } else if (array[mid] + K < array[index]) low = mid + 1; else high = mid - 1; } return 0; } private int binaryRight(int low, int high, int[] array, int index) { while (low <= high) { int mid = (low + high) / 2; if (array[mid] - K == array[index]) { // System.out.println("" + array[index] + " " + array[mid]); return 1; } else if (array[mid] - K < array[index]) low = mid + 1; else high = mid - 1; } return 0; } }

import java.io.BufferedReader; import java.io.InputStreamReader; import java.util.Arrays; /**  * This problem actually ask the coder to count the number of inversions.  * The updated merge-sort could count this number perfectly.  */ /**  * @author antonio081014  * @since Jan 8, 2012, 4:41:26 PM  */ public class Solution {     public static void main(String[] args) throws Exception {         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));         // BufferedReader br = new BufferedReader(new InputStreamReader(         // new DataInputStream(new FileInputStream("input.txt"))));         // BufferedWriter bw = new BufferedWriter(new FileWriter(new File(         // "output.txt")));         int T = Integer.parseInt(br.readLine());         for (int t = 0; t < T; t++) {             int N = Integer.parseInt(br.readLine());             int[] nums = new int[N];             String[] strs = br.readLine().split(" ");             for (int j = 0; j < N; j++)                 nums[j] = Integer.parseInt(strs[j]);             System.out.println(Long.toString(sort_and_count(nums, 0, N - 1)));             // bw.write(Long.toString(sort_and_count(nums, 0, N - 1)) + "\n");         }         // br.close();         // bw.close();     }     public static long sort_and_count(int[] a, int x1, int x2) {         if (x2 <= x1)             return 0L;         if (x2 == x1 + 1) {             if (a[x1] > a[x2]) {                 a[x1] ^= a[x2];                 a[x2] ^= a[x1];                 a[x1] ^= a[x2];                 return 1L;             }             return 0L;         }         int mid = (x2 + x1) / 2;         long count = 0L;         count += sort_and_count(a, x1, mid);         count += sort_and_count(a, mid + 1, x2);         count += merge_and_count(a, x1, mid, mid + 1, x2);         return count;     }     public static long merge_and_count(int[] a, int x1, int x2, int y1, int y2) {         long count = 0L;         for (int i = x1, j = y1; i <= x2 && j <= y2;) {             if (a[i] > a[j]) {                 count += (long) (x2 - i + 1);                 j++;             }             else                 i++;         }         Arrays.sort(a, x1, y2 + 1);         return count;     }     public static long insertSort(int[] a) {         long count = 0;         for (int i = 1; i < a.length; i++) {             int j = i;             while (j >= 1 && a[j] < a[j - 1]) {                 a[j] ^= a[j - 1];                 a[j - 1] ^= a[j];                 a[j] ^= a[j - 1];                 count++;                 j--;             }         }         return count;     } }

import java.io.BufferedReader; import java.io.InputStreamReader; /**  * Problem: 2's complement, from interviewStreet.  *  * The solution is from the link, which reached a log(n) time complexity on this  * one.  */ /**  * @author antonio081014  * @since Jan 5, 2012, 1:41:35 PM  */ public class Solution {     public static void main(String[] args) throws Exception {         // BufferedReader br = new BufferedReader(new InputStreamReader(         // new DataInputStream(new FileInputStream(args[0]))));         // BufferedWriter bw = new BufferedWriter(new FileWriter(args[1]));         BufferedReader br = new BufferedReader(new InputStreamReader(System.in));         int T = Integer.parseInt(br.readLine());         for (int t = 1; t <= T; t++) {             String[] str = br.readLine().split(" ");             int a = Integer.parseInt(str[0]);             int b = Integer.parseInt(str[1]);             System.out.println(solve(a, b));             // bw.write(Long.toString(solve(a, b)) + "\n");         }         br.close();         // bw.close();     }     /**      * http://stackoverflow.com/questions/7942732/number-of-1s-in-the-twos-      * complement-binary-representations-of-integers-in-a-ran      *       * The explanation greatly explans everything.      *      * */     public static long solve(int a, int b) {         if (a >= 0) {             long ret = counter(b);             if (a > 0)                 ret -= counter(a - 1);             return ret;         }         long ret = ((long) 32 * (-(long) a)) - counter(-a - 1);         if (b > 0)             ret += counter(b);         else if (b < -1) {             b++;             ret -= ((long) 32 * (-(long) b)) - counter(-b - 1);         }         return ret;     }     /**      * Calculate the number of 1s from number 0 to number num;      *       * */     public static long counter(int num) {         if (num == 0)             return 0L;         if (num % 2 == 0)             return counter(num - 1) + ones(num);         return (((long) num + 1) / 2) + 2 * counter(num / 2);     }     /**      * Calculate the number of 1s in the number      */     public static long ones(int num) {         String str = Integer.toBinaryString(num);         long sum = 0L;         for (int i = 0; i < str.length(); i++)             if (str.charAt(i) == '1')                 sum++;         return sum;     } }

Also, a fellow student has been posting cool stuff on our class board such as Google Summer of Code that I'd be totally interested in doing. But regardless of whether they do it again this year I'm going to attempt to get involved in open source soon. I'm looking at you, Eclipse.