代码改变世界

leetcode - Jump Game II

2013-04-21 11:33  张汉生  阅读(158)  评论(0)  编辑  收藏  举报

题目描述：点击此处

这道题的优化需要好好想想，自己想了半天才想出来，真笨。

 1 class Solution {
 2 public:
 3   int jump(int A[], int n) {
 4     // Start typing your C/C++ solution below
 5     // DO NOT write int main() function
 6     if (n<=0)
 7       return true;
 8     int *flag = new int[n];
 9     int *index = new int[n];
10     index[n-1] = 1000000000;
11     flag[n-1] = 0;
12     int i, j;
13     for (i=0; i<n-1; i++){
14       flag[i] = 1000000000;
15       index[i] = 1000000000;
16     }
17     for (i=n-2; i>=0; i--){
18       for (j=1; j<=A[i] && i+j<n;){
19         if (index[i+j]<=i+A[i]){
20           if (flag[i] > flag[i+j]){
21             flag[i] = flag[i+j];
22             index[i] = index[i+j];
23           }
24         }
25         else if (flag[i]>flag[i+j]+1){
26           flag[i] = flag[i+j] + 1;
27           index[i] = i+j;
28         }
29         if (A[i+j]>0)
30           j += A[i+j];
31         else j++;
32       }
33     }
34     int rlt = flag[0];
35     delete []index;
36     delete []flag;
37     return rlt;
38   }
39 };