LeetCode 75

Min Cost Climbing Stairs

Problem
LC 746
Topic
DP 1D
File
official75_LC746MinCostClimbingStairs.java
Path
pkg5leetcode/official75/official75_LC746MinCostClimbingStairs.java
Package
pkg5leetcode.official75
Command
java pkg5leetcode/official75/official75_LC746MinCostClimbingStairs.java
Approach
DP min cost to reach each step.
Complexity
Time O(n), Space O(1)

LeetCode solutions

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pkg5leetcode/official75/official75_LC746MinCostClimbingStairs.java
1package pkg5leetcode.official75;2 3/*4 * Min Cost Climbing Stairs | LC 7465 * APPROACH: DP min cost to reach each step.6 * COMPLEXITY: Time O(n), Space O(1)7 */8public class official75_LC746MinCostClimbingStairs {9    static int minCostClimbingStairs(int[] cost) {10        int a = 0, b = 0;11        for (int i = 2; i <= cost.length; i++) {12            int c = Math.min(b + cost[i - 1], a + cost[i - 2]);13            a = b; b = c;14        }15        return b;16    }17 18    public static void main(String[] args) {19        check(minCostClimbingStairs(new int[]{10,15,20}) == 15, "case1");20        check(minCostClimbingStairs(new int[]{1,100,1,1,1,100,1,1,100,1}) == 6, "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}