最少跳跃次数问题
此问题给出正整数列表。每个整数表示从当前元素可以进行的最大步数。从第一个元素开始,我们必须找到到列表末尾项的最少要跳的次数。
对于动态规划方法,可以定义一个 jumps 数组来存储所需的最少跳跃次数。类似 jumps[i] 的值,它表示从第 0 个索引需要多少最少跳跃次数来达到数组的第 i 个索引。
输入和输出
Input: A list of integers. {1, 3, 5, 8, 9, 2, 6, 7, 6, 8, 9} Output: The minimum number of jumps to reach the end location. It is 3. Start from value 1, go to 3. then jumps 3 values and reach 8. then jump 8 values and reach the last element.
算法
minPossibleJump(list, n)
输入:数字数组、数组中的元素数量。
输出:到末尾所需的最少跳跃次数。
Begin define an array named jump of size n if n = 0 or list[0] = 0, then return ∞ jump[0] := 0 for i := 1 to n, do jumps[i] := ∞ for j := 0 to i, do if i <= j + list[j] and jump[j] ≠ ∞, then jump[i] := minimum of jump[i] and (jump[j] + 1) break the loop done done return jump[n-1] End
示例
#include<iostream> using namespace std; int min(int x, int y) { return (x < y)? x: y; } int minPossibleJump(int list[], int n) { int *jumps = new int[n]; // dynamically create jumps array to store steps if (n == 0 || list[0] == 0) return INT_MAX; jumps[0] = 0; for (int i = 1; i < n; i++) { jumps[i] = INT_MAX; //initially set jumps as infinity for (int j = 0; j < i; j++) { if (i <= j + list[j] && jumps[j] != INT_MAX) { jumps[i] = min(jumps[i], jumps[j] + 1); break; } } } return jumps[n-1]; } int main() { int list[] = {1, 3, 5, 8, 9, 2, 6, 7, 6, 8, 9}; int size = 11; cout << "Minimum number of jumps to reach end is: "<< minPossibleJump(list,size); return 0; }
输出
Minimum number of jumps to reach end is: 3
广告