Java代码

字符串

数组

二分查找算法

public class Sample {
	public static void main(String[] args) {
		int[] arr = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
		int left = 0;
		int right = arr.length - 1;
		int mid = (left + right) / 2;
		int key = 10;
		while (arr[mid] != key) {
			if (key < arr[mid]) {
				right = mid - 1;
			}
			if (key > arr[mid]) {
				left = mid + 1;
			}
			if (left > right) {
				mid = -1;
				break;
			}
			mid = (left + right) / 2;
		}
		System.out.println(mid);
	}
}

选择排序算法

public class Sample {
	public static void main(String[] args) {
		int arr[] = { 6, 2, 4, 5, 1, 3, 7, 9, 8 };
		for (int i = 0; i < arr.length - 1; i++) {
			for (int j = i + 1; j < arr.length; j++) {
				if (arr[i] > arr[j]) {
					int temp = arr[i];
					arr[i] = arr[j];
					arr[j] = temp;
				}
			}
		}
		for (int i = 0; i < arr.length; i++) {
			System.out.print(arr[i] + " ");
		}
	}
}

递归斐波那契数列

public class fibo {
	public static void main(String[] args) {
		System.out.println(f(30));
	}

	public static int f(int n) {
		if (n == 1 || n == 2) {
			return 1;
		} else {
			return f(n - 1) + f(n - 2);
		}

	}
}