Interview 150

Jump Game II

Problem
LC 45
File
interview150_LC45JumpGameII.java
Path
pkg5leetcode/interview150/interview150_LC45JumpGameII.java
Package
pkg5leetcode.interview150
Command
java pkg5leetcode/interview150/interview150_LC45JumpGameII.java
Approach
Greedy BFS layers; count jumps when reaching current layer end.
Complexity
Time O(n), Space O(1)

LeetCode solutions

There is no in-browser runner. This is the file from the curriculum, unchanged.

pkg5leetcode/interview150/interview150_LC45JumpGameII.java
1package pkg5leetcode.interview150;2 3/*4 * Jump Game II | LC 455 * APPROACH: Greedy BFS layers; count jumps when reaching current layer end.6 * COMPLEXITY: Time O(n), Space O(1)7 */8public class interview150_LC45JumpGameII {9    static int jump(int[] nums) {10        int jumps = 0, end = 0, farthest = 0;11        for (int i = 0; i < nums.length - 1; i++) {12            farthest = Math.max(farthest, i + nums[i]);13            if (i == end) { jumps++; end = farthest; }14        }15        return jumps;16    }17 18    public static void main(String[] args) {19        check(jump(new int[]{2, 3, 1, 1, 4}) == 2, "case1");20        check(jump(new int[]{2, 1, 1, 1, 1}) == 3, "case2");21        System.out.println("all tests passed");22    }23 24    static void check(boolean cond, String name) {25        if (!cond) throw new AssertionError("FAILED: " + name);26        System.out.println("  PASS " + name);27    }28}