**一. 題目描述**
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.)
**二. 題目分析**
該題的大意是,給定一個數組,每個元素代表從該位置可以往后跳的距離,問從第一個位置跳到最后一個位置至少需要跳多少次。
與 Jump Game 有所不同的是,Jump Game 詢問該數組能否跳到最后一格,這道題要求算出跳的次數。解決的思路依舊是貪心,只需設置一個數組用來記錄跳的路徑即可。
**三. 示例代碼**
~~~
class Solution {
public:
int jump(int A[], int n)
{
int result = 0; // 當前已跳躍的次數
int last = 0; // 上一跳可達到的最遠距離
int curr = 0; // 當前一跳可達到的最遠距離
for (int i = 0; i < n; ++i)
{
// 無法向前繼跳直接返回
if(i > curr)
return -1;
// 需要進行下次跳躍,則更新last和當前已執行的跳數result
if (i > last)
{
last = curr;
++result;
}
// 更新當前可跳達的最遠處
curr = max(curr, i+A[i]);
}
return result;
}
};
~~~
**四. 小結**
類似的解題思路還有BFS,后期可以驗證驗證。
- 前言
- 2Sum
- 3Sum
- 4Sum
- 3Sum Closest
- Remove Duplicates from Sorted Array
- Remove Duplicates from Sorted Array II
- Search in Rotated Sorted Array
- Remove Element
- Merge Sorted Array
- Add Binary
- Valid Palindrome
- Permutation Sequence
- Single Number
- Single Number II
- Gray Code(2016騰訊軟件開發筆試題)
- Valid Sudoku
- Rotate Image
- Power of two
- Plus One
- Gas Station
- Set Matrix Zeroes
- Count and Say
- Climbing Stairs(斐波那契數列問題)
- Remove Nth Node From End of List
- Linked List Cycle
- Linked List Cycle 2
- Integer to Roman
- Roman to Integer
- Valid Parentheses
- Reorder List
- Path Sum
- Simplify Path
- Trapping Rain Water
- Path Sum II
- Factorial Trailing Zeroes
- Sudoku Solver
- Isomorphic Strings
- String to Integer (atoi)
- Largest Rectangle in Histogram
- Binary Tree Preorder Traversal
- Evaluate Reverse Polish Notation(逆波蘭式的計算)
- Maximum Depth of Binary Tree
- Minimum Depth of Binary Tree
- Longest Common Prefix
- Recover Binary Search Tree
- Binary Tree Level Order Traversal
- Binary Tree Level Order Traversal II
- Binary Tree Zigzag Level Order Traversal
- Sum Root to Leaf Numbers
- Anagrams
- Unique Paths
- Unique Paths II
- Triangle
- Maximum Subarray(最大子串和問題)
- House Robber
- House Robber II
- Happy Number
- Interlaving String
- Minimum Path Sum
- Edit Distance
- Best Time to Buy and Sell Stock
- Best Time to Buy and Sell Stock II
- Best Time to Buy and Sell Stock III
- Best Time to Buy and Sell Stock IV
- Decode Ways
- N-Queens
- N-Queens II
- Restore IP Addresses
- Combination Sum
- Combination Sum II
- Combination Sum III
- Construct Binary Tree from Inorder and Postorder Traversal
- Construct Binary Tree from Preorder and Inorder Traversal
- Longest Consecutive Sequence
- Word Search
- Word Search II
- Word Ladder
- Spiral Matrix
- Jump Game
- Jump Game II
- Longest Substring Without Repeating Characters
- First Missing Positive
- Sort Colors
- Search for a Range
- First Bad Version
- Search Insert Position
- Wildcard Matching