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为了帮助大家熟悉 CCF 软件能力认证考试的操作方式与答题环境,了解试题的大致难度,做好考前的准备,故在此提供试题的参考答案。Java 程序是灵活的,为了解决同一个问题,即使结果相同,程序的内容也不一定是完全一致的,仅供各位在练习时参考。
1. 出现次数最多的数
import java.util.*;public class Main { public static void main(String[] args) { new Main().run(); } public void run() { Scanner fin = new Scanner(System.in); int N = fin.nextInt(); int[] count = new int[10001]; for (int i = 0; i < N; ++i) { ++count[fin.nextInt()]; } int maxCount = -1; int result = 0; for (int i = 1; i <= 10000; ++i) { if (count[i] > maxCount) { maxCount = count[i]; result = i; } } System.out.println(result); }} 2. ISBN 号码
import java.io.BufferedReader;import java.io.InputStreamReader;public class Main { public static void main(String args[]) { BufferedReader bin = new BufferedReader(new InputStreamReader(System.in)); try{ int sum=0;char cc='0'; String isbn_0 = bin.readLine(); String isbn = isbn_0.replace("-", ""); for(int i=0; i<9; i++){ int ii = (int)isbn.charAt(i)-48; sum += ii * (i+1); } sum = sum % 11; if(sum == 10) cc = 'X';// else cc = (char)(sum+48); if(cc == isbn.charAt(9)) System.out.println("Right"); else{ isbn_0 = isbn_0.substring(0,12) + cc; System.out.println(isbn_0); } }catch(Exception e){ e.printStackTrace(); } }} 3.最大的矩形
import java.util.*;public class Main { public static void main(String[] args) { new Main().run(); } public void run() { Scanner fin = new Scanner(System.in);int N = fin.nextInt(); int[] height = new int[N]; for (int i = 0; i < N; ++i) height[i] = fin.nextInt(); int result = 0; for (int i = 0; i < N; ++i) { int width = 1; for (int j = i - 1; j >= 0; --j) { if (height[j] < height[i]) break; ++width; } for (int j = i + 1; j < N; ++j) { if (height[j] < height[i]) break; ++width; } int area = width * height[i]; result = Math.max(result, area); } System.out.println(result); }} 4.有趣的数
import java.util.*;public class Main { public static void main(String[] args) { new Main().run(); } public void run() { Scanner fin = new Scanner(System.in); int N = fin.nextInt(); long[] count = new long[8]; count[6] = 0; count[7] = 1; long mod = 1000000007;for (int i = 2; i <= N; ++i) { long[] newCount = new long[8]; newCount[0] = (count[0] * 2 + count[1] + count[3]) % mod; newCount[1] = (count[1] * 2 + count[2] + count[5]) % mod; newCount[2] = (count[2] + count[6]) % mod; newCount[3] = (count[3] * 2 + count[4] + count[5]) % mod; newCount[4] = (count[4] + count[7]) % mod; newCount[5] = (count[5] * 2 + count[6] + count[7]) % mod; newCount[6] = 0; newCount[7] = 1; count = newCount; } System.out.println(count[0]); }} 5.I’m stuck!
import java.util.*;public class Main { public static void main(String[] args) { new Main().run(); } public void run() { Scanner fin = new Scanner(System.in); int N = fin.nextInt(); long[] count = new long[8]; count[6] = 0; count[7] = 1; long mod = 1000000007;for (int i = 2; i <= N; ++i) { long[] newCount = new long[8]; newCount[0] = (count[0] * 2 + count[1] + count[3]) % mod; newCount[1] = (count[1] * 2 + count[2] + count[5]) % mod; newCount[2] = (count[2] + count[6]) % mod; newCount[3] = (count[3] * 2 + count[4] + count[5]) % mod; newCount[4] = (count[4] + count[7]) % mod; newCount[5] = (count[5] * 2 + count[6] + count[7]) % mod; newCount[6] = 0; newCount[7] = 1; count = newCount; } System.out.println(count[0]); }}5.I’m stuck!import java.util.*;public class Main { public static void main(String[] args) { new Main().run();}public void run() { Scanner fin = new Scanner(System.in); int R = fin.nextInt(); int C = fin.nextInt(); fin.nextLine(); int[][] board = new int[R + 2][C + 2]; int rowStart = 0, colStart = 0, rowEnd = 0, colEnd = 0; for (int i = 1; i <= R; ++i) { String line = fin.nextLine(); for (int j = 1; j <= C; ++j) { char c = line.charAt(j - 1); switch (c) {case '#': break; case '-': board[i][j] = 5; break; case '|': board[i][j] = 0xA; break; case '+': case 'S': case 'T': board[i][j] = 0xF; break; case '.': board[i][j] = 0x8; break; default: break; } if (c == 'S') { rowStart = i; colStart = j; } else if (c == 'T') { rowEnd = i; colEnd = j; } } } int[] dr = new int[] {0, -1, 0, 1}; int[] dc = new int[] {1, 0, -1, 0}; // Scan 1: find all cells which can reach T boolean[][] visited = new boolean[R + 2][C + 2]; boolean[][] canReachT = new boolean[R + 2][C + 2]; initVisited(visited); canReachT[rowEnd][colEnd] = true; visited[rowEnd][colEnd] = true; Queue queue = new LinkedList (); queue.add(rowEnd); queue.add(colEnd); while (!queue.isEmpty()) { int r = queue.remove(); int c = queue.remove(); for (int i = 0; i < 4; ++i) { int nr = r + dr[i];int nc = c + dc[i]; if (visited[nr][nc]) continue; if ((board[nr][nc] & (1 << ((i + 2) % 4))) != 0) { canReachT[nr][nc] = true; queue.add(nr); queue.add(nc); visited[nr][nc] = true; } } } /* for (int i = 1; i <= R; ++i) { for (int j = 1; j <= C; ++j) { if (canReachT[i][j]) { System.out.println("i = " + i + ", j = " + j); } } } */ if (!canReachT[rowStart][colStart]) { System.out.println("I'm stuck!"); return; } // Scan 2: get result boolean[][] rCanReach = new boolean[R + 2][C + 2]; initVisited(visited); queue.clear(); visited[rowStart][colStart] = true; rCanReach[rowStart][colStart] = true; queue.add(rowStart); queue.add(colStart); while (!queue.isEmpty()) { int r = queue.remove(); int c = queue.remove(); for (int i = 0; i < 4; ++i) { if ((board[r][c] & (1 << i)) == 0) continue;int nr = r + dr[i]; int nc = c + dc[i]; if (visited[nr][nc]) continue; if (board[nr][nc] == 0) continue; rCanReach[nr][nc] = true; queue.add(nr); queue.add(nc); visited[nr][nc] = true; } } int result = 0; for (int i = 1; i <= R; ++i) { for (int j = 1; j <= C; ++j) { /* if (rCanReach[i][j]) { System.out.println("i = " + i + ", j = " + j); } */ if (rCanReach[i][j] && (!canReachT[i][j])) ++result; } } System.out.println(result);}private void initVisited(boolean[][] visited) { int R = visited.length - 2; int C = visited[0].length - 2; for (int i = 0; i <= R + 1; ++i) { visited[i][0] = true; visited[i][C + 1] = true; } for (int j = 0; j <= C + 1; ++j) { visited[0][j] = true; visited[R + 1][j] = true; } for (int i = 1; i <= R; ++i) { for (int j = 1; j <= C; ++j) { visited[i][j] = false;} } }}