01串的魔法

思路：虽然标着dp，其实是滑动窗口问题，dp 会超时

import java.util.*;public class Main {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);int n = scanner.nextInt();int k = scanner.nextInt();int arr[] = new int[n];int max = 0;int left = 0;int right = 0;int cnt = 0;for(int i=0;i<n;i++)arr[i] = scanner.nextInt();while(right<n){if(arr[right]==0)cnt++;while(cnt>k){if(arr[left]==0)cnt--;left++;}if(right - left + 1 > max)max = right - left + 1;right ++ ;}System.out.println(max);}
}

dp解法也写了，先是超空间，优化后又超时间

import java.util.*;public class Main {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);int n = scanner.nextInt();int k = scanner.nextInt();int arr[] = new int[n+1];int dp[][] = new int[2][k+1];int max = 0;for(int i=1;i<=n;i++)arr[i] = scanner.nextInt();for(int i=1;i<=n;i++){dp[1][0] = arr[i]==1?dp[0][0]+1:0;for(int j=1;j<=k;j++){if(arr[i]==0) dp[1][j] = dp[0][j-1] + 1;else dp[1][j] = dp[0][j] + 1;}max = Math.max(max,dp[1][k]);for(int j=0;j<=k;j++){dp[0][j] = dp[1][j];dp[1][j] = 0;}}System.out.println(max);}
}

上台阶

import java.util.*;public class Main {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);int n = scanner.nextInt();int dp[] = new int[101];dp[1] = 1;dp[2] = 1;for(int i = 3;i<=100;i++)dp[i] = dp[i-1] + dp[i-2];dp[1] = 0;for(int i=0;i<n;i++){int m = scanner.nextInt();System.out.println(dp[m]);}}
}

triangle

思路：只有斐波那契数列三三之间不能组成三角形，把剩下的都剔除

import java.util.*;public class Main {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);int fib[] = new int[40];fib[0] = 1;fib[1] = 1;for(int i=2;i<30;i++){fib[i] = fib[i-1]+fib[i-2];}while (scanner.hasNext()){int m = scanner.nextInt();int cnt  = 0;for(int i = 1;i<30;i++){if(fib[i]<=m)cnt++;else break;}System.out.println(m-cnt);}}
}