Jump Game II

来源：互联网发布：php购物车提交订单编辑：程序博客网时间：2024/05/01 06:49

看完题第一感觉，单源最短路，于是敲完代码，提交，超时。

之后仔细想了想，广搜可以解题。

广搜：

public class Solution {    public int jump(int[] A) {        // Start typing your Java solution below        // DO NOT write main() function        int len = A.length;        if(len <= 1) return 0;        int []dist = new int[len];        dist[0] = 0;        int maxIndex = 0;        for(int i=0;i<=maxIndex;i++) {            int pos = i + A[i];        if(pos >= len-1) return dist[i] + 1;        if(pos > maxIndex) {        for(int j=maxIndex+1; j<=pos; j++) {        dist[j] = dist[i] + 1;        }        maxIndex = pos;        }        }        return dist[len-1];    }}

单源最短路径：

import java.util.Arrays;public class Solution {public static final int MAX = (int) Math.pow(2, 30);public int jump(int[] A) {        // Start typing your Java solution below        // DO NOT write main() function        int len = A.length;        if(len == 0) return 0;        boolean []isVisited = new boolean[len+1];        Arrays.fill(isVisited, false);        int []dist = new int[len+1];        dist[0] = 0;        for(int i=1;i<len;i++) dist[i] = A[0] >= i ? 1 : MAX;        isVisited[0] = true;        int CASE = len - 1;        while(CASE-- > 0) {        int min = MAX, index = 0;        for(int i=0;i<len;i++) {        if(isVisited[i]==false && dist[i]<min) {        min = dist[i];        index = i;        }        }        isVisited[index] = true;        if(index == len-1) return min;                for(int i=index+1;i<len;i++) {        int len_index_i = A[index] >= i - index ? 1 : MAX;        if(isVisited[i]==false && dist[index]+len_index_i<dist[i])        dist[i] = dist[index] + len_index_i;        }        }        return dist[len-1];    }//public static void main(String[] args) {//Solution s = new Solution();//int []a = new int[30000];//for(int i=0;i<30000;i++) a[i] = 3000 - i;//System.out.println(s.jump(a));//}}