挑战程序竞赛系列（68）：4.7字符串匹配（3）
题意：
找茬：从大图中找出特定方块小图，旋转翻转皆可。
先编码，后hash计算，最后匹配输出结果，和书上一个思路。
代码如下：
代码语言：javascript复制import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.StringTokenizer;
public class Main{
String INPUT = "./data/judge/201709/A1312.txt";
public static void main(String[] args) throws IOException {
new Main().run();
}
static final long B1 = 9973;
static final long B2 = 1000000007;
int base64(char ch) {
if (ch >= 'A' && ch <= 'Z') {
return ch - 'A';
}
if (ch >= 'a' && ch <= 'z') {
return ch - 'a' 26;
}
if (ch >= '0' && ch <= '9') {
return ch - '0' 52;
}
return ch == ' ' ? 62 : 63;
}
void base64_to_bit(char[][] raw, int[][] bit, int n) {
for (int i = 0; i < n; i) {
for (int j = 0; j < raw[i].length; j) {
int base = base64(raw[i][j]);
for (int k = 0; k < 6; k) {
bit[i][j * 6 5 - k] = (base >> k) & 1;
}
}
}
}
long computePatternHash(int[][] bit, int n, int m){
long[][] hs = new long[n][m];
for (int i = 0; i < n; i) {
for (int j = 0; j < m; j) {
hs[i][j] = (j > 0 ? hs[i][j - 1] : 0) * B1 bit[i][j];
}
}
long[][] hs2 = new long[n][m];
for (int j = 0; j < m; j) {
for (int i = 0; i < n; i) {
hs2[i][j] = (i > 0 ? hs2[i - 1][j] : 0) * B2 hs[i][j];
}
}
return hs2[n - 1][m - 1];
}
long[][] computeHash(int[][] imageBit, int n, int m, int p){
long[][] hs = new long[n][m];
for (int i = 0; i < n; i) {
long pw = 1;
for (int j = 0; j < p; j) {
hs[i][j] = (j > 0 ? hs[i][j - 1] : 0) * B1 imageBit[i][j];
pw *= B1;
}
for (int j = p; j < m; j) {
hs[i][j] = hs[i][j - 1] * B1 imageBit[i][j] - pw * imageBit[i][j - p];
}
}
long[][] hs2 = new long[n][m];
for (int j = 0; j < m; j) {
long pw = 1;
for (int i = 0; i < p; i) {
hs2[i][j] = (i > 0 ? hs2[i - 1][j] : 0) * B2 hs[i][j];
pw *= B2;
}
for (int i = p; i < n; i) {
hs2[i][j] = hs2[i - 1][j] * B2 hs[i][j] - pw * hs[i - p][j];
}
}
return hs2;
}
void rotate(int[][] bit, int n) {
int[][] tmp = new int[n][n];
for (int i = 0; i < n; i) {
for (int j = 0; j < n; j) {
tmp[i][j] = bit[i][j];
}
}
for (int i = 0; i < n; i) {
for (int j = 0; j < n; j) {
bit[j][n - i - 1] = tmp[i][j];
}
}
}
void overturn(int[][] bit, int n) {
int[][] tmp = new int[n][n];
for (int i = 0; i < n; i) {
for (int j = 0; j < n; j) {
tmp[i][j] = bit[i][j];
}
}
for (int i = 0; i < n; i) {
for (int j = 0; j < n; j) {
bit[i][n - j - 1] = tmp[i][j];
}
}
}
void read() {
while (true) {
int W = ni();
int H = ni();
int P = ni();
if (W P H == 0) break;
char[][] image = new char[H][];
char[][] pattern = new char[P][];
for (int i = 0; i < H; i) {
image[i] = ns().toCharArray();
}
for (int i = 0; i < P; i) {
pattern[i] = ns().toCharArray();
}
if (H < P || W < P) {
out.println(0);
continue;
}
int[][] imageBit = new int[H][1024];
int[][] patternBit = new int[P][128];
base64_to_bit(image, imageBit, H);
base64_to_bit(pattern, patternBit, P);
Map<Long, Integer> mem = new HashMap<>();
for (int d = 0; d < 8; d) {
rotate(patternBit, P);
if (d == 4) {
overturn(patternBit, P);
}
long pat = computePatternHash(patternBit, P, P);
Num.inc(mem, pat);
}
long[][] hs = computeHash(imageBit, H, W, P);
int ans = 0;
for (int i = 0; i < H; i) {
for (int j = 0; j < W; j) {
if (i >= P - 1 && j >= P - 1) {
if (mem.containsKey(hs[i][j])) {
ans ;
}
}
}
}
out.println(ans);
}
}
FastScanner in;
PrintWriter out;
void run() throws IOException {
boolean oj;
try {
oj = ! System.getProperty("user.dir").equals("F:\java_workspace\leetcode");
} catch (Exception e) {
oj = System.getProperty("ONLINE_JUDGE") != null;
}
InputStream is = oj ? System.in : new FileInputStream(new File(INPUT));
in = new FastScanner(is);
out = new PrintWriter(System.out);
long s = System.currentTimeMillis();
read();
out.flush();
if (!oj){
System.out.println("[" (System.currentTimeMillis() - s) "ms]");
}
}
public boolean more(){
return in.hasNext();
}
public int ni(){
return in.nextInt();
}
public long nl(){
return in.nextLong();
}
public double nd(){
return in.nextDouble();
}
public String ns(){
return in.nextString();
}
public char nc(){
return in.nextChar();
}
class FastScanner {
BufferedReader br;
StringTokenizer st;
boolean hasNext;
public FastScanner(InputStream is) throws IOException {
br = new BufferedReader(new InputStreamReader(is));
hasNext = true;
}
public String nextToken() {
while (st == null || !st.hasMoreTokens()) {
try {
st = new StringTokenizer(br.readLine());
} catch (Exception e) {
hasNext = false;
return "##";
}
}
return st.nextToken();
}
String next = null;
public boolean hasNext(){
next = nextToken();
return hasNext;
}
public int nextInt() {
if (next == null){
hasNext();
}
String more = next;
next = null;
return Integer.parseInt(more);
}
public long nextLong() {
if (next == null){
hasNext();
}
String more = next;
next = null;
return Long.parseLong(more);
}
public double nextDouble() {
if (next == null){
hasNext();
}
String more = next;
next = null;
return Double.parseDouble(more);
}
public String nextString(){
if (next == null){
hasNext();
}
String more = next;
next = null;
return more;
}
public char nextChar(){
if (next == null){
hasNext();
}
String more = next;
next = null;
return more.charAt(0);
}
}
static class ArrayUtils {
public static void fill(int[][] f, int value) {
for (int i = 0; i < f.length; i) {
Arrays.fill(f[i], value);
}
}
public static void fill(int[][][] f, int value) {
for (int i = 0; i < f.length; i) {
fill(f[i], value);
}
}
public static void fill(int[][][][] f, int value) {
for (int i = 0; i < f.length; i) {
fill(f[i], value);
}
}
}
static class Num{
public static <K> void inc(Map<K, Integer> mem, K k) {
if (!mem.containsKey(k)) mem.put(k, 0);
mem.put(k, mem.get(k) 1);
}
}
static class D{
public static void pp(int[][] board, int row, int col) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < row; i) {
for (int j = 0; j < col; j) {
sb.append(board[i][j] (j 1 == col ? "n" : " "));
}
}
System.out.println(sb.toString());
}
public static void pp(char[][] board, int row, int col) {
StringBuilder sb = new StringBuilder();
for (int i = 0; i < row; i) {
for (int j = 0; j < col; j) {
sb.append(board[i][j] (j 1 == col ? "n" : " "));
}
}
System.out.println(sb.toString());
}
}
}
