跳跃游戏 II

题目：力扣

class Solution {
    public int jump(int[] nums) {
        int length = nums.length;
        int end = 0;
        int maxPosition = 0; 
        int steps = 0;
        for (int i = 0; i < length - 1; i++) {
            maxPosition = Math.max(maxPosition, i + nums[i]); 
            if (i == end) {
                end = maxPosition;
                steps++;
            }
        }
        return steps;
    }
}

 

 

超时代码： 

class Solution {
    int res = Integer.MAX_VALUE;
    public int jump(int[] nums) {
        int[] jump = new int[nums.length];
        for(int i = 0 ; i < nums.length-1; i++){
            int jump_num = nums[i];
            for(int j = i+1; j < nums.length && j <= i+nums[i]; j++){
                if(jump[j]!=0){
                    jump[j] = Math.min(jump[i]+1,jump[j]);
                }
                else{
                    jump[j] = jump[i]+1;
                }
            }
            if(jump[nums.length-1] != 0){
                return jump[nums.length-1];
            }
        }
        return jump[nums.length-1];
    }
}