java常用演算法

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冒泡排序：

    //降序    public static int[] bubbleSort(int[] array){        for(int i = 0; i < array.length; i++){            int curval = array[i];            for(int j = i - 1; j >= 0; j--){                int temp = array[j];                if(curval > temp){                    array[j] = curval;                    array[j+1] = temp;                }            }        }        return array;    }

    //升序    public static int[] bubbleSort(int[] array){        for(int i = array.length - 1; i >= 0; i--){            int curval = array[i];            for(int j = i; j < array.length-1; j++){                int tempval = array[j+1];                if(tempval < curval){                    array[j+1] = curval;                    array[j] = tempval;                }            }        }        return array;    }

二分法尋找

//降序    public static int binarySearch (int[] array, int search){        int start = 0;        int end = array.length-1;        int middle = array.length / 2;        for(; start <= end; ){            middle = (start + end) / 2;            int val = array[middle];            if(val == search){                return middle;            }else if(val > search){                start = middle + 1;            }else{                end = middle - 1;            }        }                return -1;            }

　　//升序    public static int binarySearch(int[] array, int search){        int start = 0;        int end = array.length - 1;        int middle = (start + end) / 2;        for(;start <= end;){            middle = (start + end) / 2;            int midval = array[middle];            if(midval > search){                end = middle - 1;            }else if(midval < search){                start = middle + 1;            }else{                return middle;            }        }        return -1;    }

 調用

    public static void main(String[] args){        int[] test = new int[]{1,200,164,29,298,188,34,52,287,100,33};        int[] bubres = bubbleSort(test);        for(int i = 0; i < bubres.length; i++){            System.out.println(i + "*************" + bubres[i]);        }                System.out.println("-----*****" + binarySearch(bubres, 1));    }

 

java常用演算法