55.Jump Game

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Riguz留言 | 贡献2023年10月10日 (二) 23:04的版本 (Created page with "=Description= {{LeetCode |id=jump-game |no=55 |difficulty=Medium |category=Dynamic Programming |collection=Top 150 |title=Triangle |summary=You are given an integer array nums. You are initially positioned at the array's first index, and each element in the array represents your maximum jump length at that position. Return true if you can reach the last index, or false otherwise.}} Example 1: <syntaxhighlight lang="bash"> Input: nums = [2,3,1,1,4] Output: true </synta...")
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Description

#55 Triangle Medium
Dynamic Programming Top 150
You are given an integer array nums. You are initially positioned at the array's first index, and each element in the array represents your maximum jump length at that position. Return true if you can reach the last index, or false otherwise.

Example 1:

Input: nums = [2,3,1,1,4]
Output: true

Explanation: Jump 1 step from index 0 to 1, then 3 steps to the last index. Example 2:

Input: nums = [3,2,1,0,4]
Output: false

Explanation: You will always arrive at index 3 no matter what. Its maximum jump length is 0, which makes it impossible to reach the last index.

Solution

1D DP

class Solution {
    public boolean canJump(int[] nums) {
        /*
            [2,3,1,1,4]
             1 1 2 2 2
         */
        int []dp = new int[nums.length];
        dp[0] = 1;
        for(int i = 0; i < nums.length; i++) {
            for(int j = 1; j <= nums[i]; j++){
                if(i+j >= dp.length) break;
                dp[i+j]++;
            }
                
        }
        for(int i = 0; i < dp.length; i++) {
            if(dp[i] == 0) return false;
        }
            
        return true;
    }
}