uva297

来源：互联网发布：四川省委党校网络教育编辑：程序博客网时间：2024/05/29 05:55

思路：递归构造四分树，然后递归相加四分树，最后递归统计每层的黑色格子数

java实现，输入略，代码比较长而且累赘

package test;import java.util.Scanner;public class Test{static Scanner sc = new Scanner(System.in);static String line;static class Node{int value;Node[] next;@Overridepublic String toString() {if(next==null){return value+",";}else{return value+":"+next[0]+next[1]+next[2]+next[3];}}}/** * 递归构造四分树 * @param root * @param start * @param arr * @return */static int build(Node root,int start,char[] arr){int count = -1;while(count++<3&&start<arr.length){Node n = new Node();root.next[count] = n;if(arr[start]=='p'){n.value = 2;n.next = new Node[4];start = build(n,++start,arr);}else if(arr[start]=='f'){n.value = 1;start++;}else if(arr[start]=='e'){n.value = 0;start++;}}return start;}/** * 四分树root=四分树roo1+四分树root2 * @param root * @param root1 * @param root2 */static void add(Node root,Node root1,Node root2){if(root1.value==1 || root2.value==1){root.value = 1;return;}else if(root1.value==2 && root2.value==0){root.value = 2;root.next = root1.next;}else if(root1.value==0 && root2.value==2){root.value = 2;root.next = root2.next;}else if(root1.value==0 && root2.value==0){root.value = 0;return;}else if(root1.value==2 && root2.value==2){root.next = new Node[4];for(int i=0;i<4;i++){root.next[i] = new Node();add(root.next[i],root1.next[i],root2.next[i]);}}}static int[] re = new int[100];static int sum = 0;/** * 递归计算每层的黑色 * 利用re数组的index标示第几层黑色的个数 * @param root */static void count(Node root){if(root.next!=null){for(Node n:root.next){if(n.value==1){re[sum]++;}else if(n.value==2){sum++;count(n);sum--;}}}}public static void main(String[] args) {String str1 = "peeefpffeefe";Node root1 = new Node();root1.next = new Node[4];root1.value = 2;build(root1,0,str1.toCharArray());System.out.println(root1);String str2 = "efepeefe";Node root2 = new Node();root2.next = new Node[4];root2.value = 2;build(root2,0,str2.toCharArray());System.out.println(root2);Node root = new Node();root.value = 2;add(root,root1,root2);System.out.println(root);count(root);int allblack = 0;int i = 0;/** * 从上到下，如果有下层，则原黑色个数乘以4，再加上下层黑色 */while(re[i]!=0){allblack = re[i] + allblack*4;i++;}System.out.println(allblack*64);}}

另外一种思路更加直观：

package test;import java.util.Scanner;public class Test{static Scanner sc = new Scanner(System.in);static String line;static int[][] buf = new int[32][32];static int p = 0,cnt=0;//当前字符位置/** * 画出(r,c)为左上角，边长为w的四分树 * @param s * @param r * @param c * @param w */static void draw(char[] s,int r,int c,int w){char ch = s[p++];if(ch=='p'){draw(s,r,c,w/2);draw(s,r+w/2,c,w/2);draw(s,r,c+w/2,w/2);draw(s,r+w/2,c+w/2,w/2);}else if(ch=='f'){//如果是黑色，则子树都是黑色for(int i=r;i<r+w;i++){for(int j=c;j<c+w;j++){if(buf[i][j]==0){buf[i][j]=1;cnt++;}}}}}public static void main(String[] args) {p=0;String str1 = "ppeeefpffeefe";draw(str1.toCharArray(), 0, 0, 32);p=0;String str2 = "pefepeefe";draw(str2.toCharArray(), 0, 0, 32);System.out.println(cnt);}}

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