问题出在最后一层台阶不是终点,还需要再上一个台阶,所以要再来一次Math.min(dp[n-1]+cost[n-1],dp[n-2]+cost[n-2]) import java.util.Scanner; public class q2 { public static void main(String[] args){ Scanner scanner = new Scanner(System.in); String s = scanner.next(); String[] strs = s.split(","); int n = strs.length; int[] cost = new int[n]; for (int i = 0; i < n; i++) { cost[i] = Integer.parseInt(strs[i]); } int dp[] = new int[n]; dp[0] = 0; dp[1] = 0; for (int i = 2; i < n; i++) { dp[i] = Math.min(dp[i-1]+cost[i-1],dp[i-2]+cost[i-2]); } System.out.print(Math.min(dp[n-1]+cost[n-1],dp[n-2]+cost[n-2])); } }