ACM —— 1009 Edge Detection

解题代码：

package acm1009;import java.util.Arrays;import java.util.HashMap;import java.util.Scanner;public class Main {static int mWidth, mHight;static int[][] pairs = new int[1009][2];static HashMap<Integer, Integer> outMap = new HashMap<Integer, Integer>();public static void main(String[] args) {Scanner stdin = new Scanner(System.in);while ((mWidth = stdin.nextInt()) != 0) {int num = 0;int totleLen = 0;outMap.clear();while (!(((pairs[num][0] = stdin.nextInt()) == 0)&((pairs[num][1] = stdin.nextInt()) == 0))) {totleLen += pairs[num++][1];}mHight = totleLen/mWidth;findEdges(num);outputImage(totleLen);}System.out.println("0");}private static void outputImage(int totleLen) {System.out.println(mWidth);Object[] keySet = outMap.keySet().toArray();Arrays.sort(keySet);int tempKey = Integer.parseInt(keySet[0].toString());int temp = outMap.get(tempKey);for (Object k : keySet) {int key = Integer.parseInt(k.toString());if (outMap.get(key) == temp) {continue;}System.out.println(temp + " " + (key -tempKey));temp = outMap.get(key);tempKey = key;}System.out.println(temp + " " + (totleLen -tempKey));System.out.println("0 0");}private static void findEdges(int num) {int pos = 0;int x,y;for (int p = 0; p <= num; p++) {x = pos/mWidth;y = pos%mWidth;for (int i = x-1; i <= x+1; i++) {if (i < 0|| i >= mHight) {continue;}for (int j = y-1; j <=y+1; j++) {if (j < 0||j >= mWidth) {continue;}int currPos = i*mWidth + j;outMap.put(currPos, getMaxValue(currPos));}}pos += pairs[p][1];}}private static Integer getMaxValue(int currPos) {int num=getnum(currPos),ret=0;       int row=currPos/mWidth;    int col=currPos%mWidth;       for (int i=row-1;i<=row+1;i++) {if (i < 0|| i >= mHight) {continue;}        for (int j=col-1;j<=col+1;j++)        {            int tpos= i*mWidth+j;            if (j<0||j>=mWidth|| tpos==currPos)                continue;                           int tmp=getnum(tpos);            if (Math.abs(tmp-num)>ret)ret=Math.abs(tmp-num);        }    }    return ret;}private static int getnum(int currPos) {    int p=0,i=0;    while (p<=currPos)        p+=pairs[i++][1];           return pairs[i-1][0];}}

注意* 跳跃式计算，第一个点和最后一个点要单算，不然会WA！