Leetcode 题解系列（七）

45. Jump Game II

题目要求

Given an array of non-negative integers, you are initially positioned at the first index of the array.
Each element in the array represents your maximum jump length at that position.
Your goal is to reach the last index in the minimum number of jumps.
For example:
Given array A = [2,3,1,1,4]
The minimum number of jumps to reach the last index is 2. (Jump 1 step from index 0 to 1, then 3 steps to the last index.)

Note:
You can assume that you can always reach the last index.

题目分析

贪心算法

最优的一步应当是下一步最远的走法，于是有：

class Solution { public:  int jump(vector<int>& nums) {    int jumps = 0, curEnd = 0, curFarthest = 0;    for (int i = 0; i < nums.size() - 1; i++) {      curFarthest = max(curFarthest, i + nums[i]);      if (i == curEnd) {        jumps++;        curEnd = curFarthest;      }    }    return jumps;  }};